CriticalCVE-2021-26858

    Microsoft Exchange Server Remote Code Execution Vulnerability (CVE-2021-26858)

    Published Last modified In CISA KEV since Sources: SingCERT, CVE.org

    What is affected, what to do

    Microsoft Exchange Server Remote Code Execution Vulnerability

    The vulnerability is being actively exploited; treat it as a priority. CISA lists it as used in ransomware campaigns. Update Microsoft Exchange Server 2013 Cumulative Update 21 to version 15.00.1395.012, Microsoft Exchange Server 2013 Cumulative Update 22 to version 15.00.1473.006, Microsoft Exchange Server 2013 Cumulative Update 23 to version 15.00.1497.012. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Microsoft Exchange Server 2013 Cumulative Update 21 lt 15.00.0..15.00.1395.012
    • Microsoft Exchange Server 2013 Cumulative Update 22 lt 15.00.0..15.00.1473.006
    • Microsoft Exchange Server 2013 Cumulative Update 23 lt 15.00.0..15.00.1497.012
    • Microsoft Exchange Server 2016 Cumulative Update 10 lt 15.01.0..15.01.1531.012
    • Microsoft Exchange Server 2016 Cumulative Update 11 lt 15.01.0..15.01.1591.018
    • Microsoft Exchange Server 2016 Cumulative Update 12 lt 15.01.0..15.01.1713.010
    • Microsoft Exchange Server 2016 Cumulative Update 13 lt 15.01.0..15.01.1779.008
    • Microsoft Exchange Server 2016 Cumulative Update 14 lt 15.01.0..15.01.1847.012
    • Microsoft Exchange Server 2016 Cumulative Update 15 lt 15.01.0..15.01.1913.012
    • Microsoft Exchange Server 2016 Cumulative Update 16 lt 15.01.0..15.01.1979.008
    • Microsoft Exchange Server 2016 Cumulative Update 17 lt 15.01.0..15.01.2044.013
    • Microsoft Exchange Server 2016 Cumulative Update 18 lt 15.01.0..15.01.2106.013
    • Microsoft Exchange Server 2016 Cumulative Update 19 lt 15.01.0..15.01.2176.009
    • Microsoft Exchange Server 2016 Cumulative Update 8 lt 15.01.0..15.01.1415.010
    • Microsoft Exchange Server 2016 Cumulative Update 9 lt 15.01.0..15.01.1466.016
    • Microsoft Exchange Server 2019 lt 15.02.0..15.02.0221.018
    • Microsoft Exchange Server 2019 Cumulative Update 1 lt 15.02.0..15.01.1979.006
    • Microsoft Exchange Server 2019 Cumulative Update 2 lt 15.02.0..15.02.0397.011
    • Microsoft Exchange Server 2019 Cumulative Update 3 lt 15.02.0..15.02.0464.015
    • Microsoft Exchange Server 2019 Cumulative Update 4 lt 15.02.0..15.02.0659.012
    • Microsoft Exchange Server 2019 Cumulative Update 5 lt 15.02.0..15.02.0595.008
    • Microsoft Exchange Server 2019 Cumulative Update 6 lt 15.02.0..15.02.0529.013
    • Microsoft Exchange Server 2019 Cumulative Update 7 lt 15.02.0..15.02.0721.013
    • Microsoft Exchange Server 2019 Cumulative Update 8 lt 15.02.0..15.02.0792.010
    Fixed in
    • Microsoft Exchange Server 2013 Cumulative Update 21 15.00.1395.012
    • Microsoft Exchange Server 2013 Cumulative Update 22 15.00.1473.006
    • Microsoft Exchange Server 2013 Cumulative Update 23 15.00.1497.012
    • Microsoft Exchange Server 2016 Cumulative Update 10 15.01.1531.012
    • Microsoft Exchange Server 2016 Cumulative Update 11 15.01.1591.018
    • Microsoft Exchange Server 2016 Cumulative Update 12 15.01.1713.010
    • Microsoft Exchange Server 2016 Cumulative Update 13 15.01.1779.008
    • Microsoft Exchange Server 2016 Cumulative Update 14 15.01.1847.012
    • Microsoft Exchange Server 2016 Cumulative Update 15 15.01.1913.012
    • Microsoft Exchange Server 2016 Cumulative Update 16 15.01.1979.008
    • Microsoft Exchange Server 2016 Cumulative Update 17 15.01.2044.013
    • Microsoft Exchange Server 2016 Cumulative Update 18 15.01.2106.013
    • Microsoft Exchange Server 2016 Cumulative Update 19 15.01.2176.009
    • Microsoft Exchange Server 2016 Cumulative Update 8 15.01.1415.010
    • Microsoft Exchange Server 2016 Cumulative Update 9 15.01.1466.016
    • Microsoft Exchange Server 2019 15.02.0221.018
    • Microsoft Exchange Server 2019 Cumulative Update 1 15.01.1979.006
    • Microsoft Exchange Server 2019 Cumulative Update 2 15.02.0397.011
    • Microsoft Exchange Server 2019 Cumulative Update 3 15.02.0464.015
    • Microsoft Exchange Server 2019 Cumulative Update 4 15.02.0659.012
    • Microsoft Exchange Server 2019 Cumulative Update 5 15.02.0595.008
    • Microsoft Exchange Server 2019 Cumulative Update 6 15.02.0529.013
    • Microsoft Exchange Server 2019 Cumulative Update 7 15.02.0721.013
    • Microsoft Exchange Server 2019 Cumulative Update 8 15.02.0792.010

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    7.8

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: NVD, CVSS v3

    7.8

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: SingCERT, CVE.org

    93.7 %

    EPSS score

    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.

    Source: FIRST EPSS, percentile 99.84

    Show all metrics
    Severity
    Critical
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    243.74 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    actively exploitedSource: ANSSI / CERT-FR, CSA/SingCERT How we classify
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    7.8 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    7.8
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    93.7 %
    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    99.84
    Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    Actively exploited
    Published
    In CISA KEV since

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    CISA assessment (SSVC)
    Exploitation: active · automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 12 August 2026

    Response and mitigation

    Why act now?

    Prioritisation rationale

    On its own, CVE-2021-26858 requires authentication. In the ProxyLogon chain, however, CVE-2021-26855 supplies that access without credentials, giving full takeover of any network-reachable Exchange server. That is why it ranks among the CVEs most likely to be exploited. CISA flags known ransomware use: following the 2021 mass exploitation, dropped web shells were widely reused for follow-on access, data theft and encryption campaigns, hitting mid-market firms, municipalities and critical-infrastructure operators running on-prem Exchange. Treat any still-unpatched, internet-facing Exchange server as critical and probably already compromised. Patched servers that have never been checked for web shells still deserve high priority; internal-only servers rank medium.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Check exposure and pull Exchange off the internet: If an on-prem Exchange server publishes OWA/ECP on TCP 443 to the internet and is unpatched, block access at the perimeter now or restrict it to VPN only. CVE-2021-26858 is exploited without prior authentication when chained with CVE-2021-26855 (SSRF) in ProxyLogon.
      • Apply the security update: Install Microsoft's March 2021 security update for your CU level. Minimum fixed builds per context:
        • Exchange 2013: CU21 → 15.00.1395.012, CU22 → 15.00.1473.006, CU23 → 15.00.1497.012
        • Exchange 2016: CU10 → 15.01.1531.012, CU11 → 15.01.1591.018, CU12 → 15.01.1713.010, CU13 → 15.01.1779.008, CU14 → 15.01.1847.012
        • Move older CUs to a supported CU first. Look up the KB number in the Microsoft advisory. Verify the build with Get-ExchangeServer | fl Name,AdminDisplayVersion and the ExSetup.exe file version.
      • Assume compromise; patching is not enough: The update does not remove web shells already dropped. Run Microsoft's Test-ProxyLogon.ps1 and MSERT, or the Exchange On-premises Mitigation Tool (EOMT), on every Exchange server.
      • Preserve evidence on any hit: Before cleanup, capture memory, IIS logs, Exchange logs and the web shell files. Network-isolate the host.
      • Rotate credentials: On confirmed compromise, rotate Exchange service and admin account passwords and review membership of privileged AD groups. Exchange holds broad AD rights, so assume LSASS dumping occurred.
      • Check reporting obligations: For a confirmed incident, prepare the NIS2 early warning to the national CSIRT/BSI within 24 h.
    2. Runbook step 2

      Mitigation layers

      • Network: Allow inbound HTTPS to Exchange only via a reverse proxy or VPN. Restrict Exchange server egress to what is required (updates, smarthost) to hamper web shell C2 and exfiltration.
      • WAF/IIS rewrite (interim): Apply the URL Rewrite rule shipped with EOMT or Microsoft's interim mitigation. It blocks requests carrying the X-AnonResource-Backend cookie or a malformed X-BEResource cookie (the CVE-2021-26855 link). Also enable ProxyLogon IPS signatures (Suricata ET "Exchange ProxyLogon").
      • Feature reduction: Where feasible, disable the Unified Messaging, ECP and OAB application pools/virtual directories. This is disruptive and meant as a stopgap only.
      • Endpoint hardening: Enable the Defender ASR rule "Block Webshell creation for Servers" or the equivalent EDR control. Use AppLocker/WDAC to monitor or block cmd.exe/powershell.exe launched as children of w3wp.exe and UMWorkerProcess.exe.
      • File system: Put inetpub\wwwroot\aspnet_client\ and ...\FrontEnd\HttpProxy\owa\auth\ under file integrity monitoring.
      • Lifecycle: Exchange 2013 and 2016 are out of support. Record migration to a supported version or Exchange Online as a tracked risk item.
    3. Runbook step 3

      Detection rules

      • OAB generator log (specific to CVE-2021-26858): Search for "Download failed and temporary file". Hits indicate abusive file writes:
        • findstr /snip /c:"Download failed and temporary file" "%PROGRAMFILES%\Microsoft\Exchange Server\V15\Logging\OABGeneratorLog\*.log"
      • Sysmon EID 11 / EDR file create: New .aspx files written by w3wp.exe or UMWorkerProcess.exe.
        • Sigma shape: Image|endswith: ['\w3wp.exe','\UMWorkerProcess.exe'] AND TargetFilename|endswith: '.aspx'
        • Focus on the aspnet_client and owa\auth paths.
      • Process ancestry (Sysmon EID 1 / Event ID 4688): w3wp.exe (MSExchange*AppPool) or UMWorkerProcess.exe spawning cmd.exe, powershell.exe, net.exe or procdump. Also watch for handle access to lsass.exe.
        • KQL: DeviceProcessEvents | where InitiatingProcessFileName in~ ("w3wp.exe","UMWorkerProcess.exe") and FileName in~ ("cmd.exe","powershell.exe")
      • IIS logs: POSTs to /ecp/*.js (e.g. /ecp/y.js) and hits on unfamiliar .aspx under /owa/auth/ or /aspnet_client/. In the HttpProxy logs, look for AnchorMailbox values containing ServerInfo~.
      • Network (Zeek/Suricata): Outbound connections from Exchange servers to unknown IPs. Large ZIP/7z archives appearing in web directories also indicate mailbox exfiltration.

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    Microsoft Exchange Server Remote Code Execution Vulnerability

    Source: CSA/SingCERT, cvelistv5, NVD (NIST), CISA KEV Catalog, CVE.org (MITRE)

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    MicrosoftMicrosoft Exchange Server 2013 Cumulative Update 21
    • 15.00.0 – < 15.00.1395.012
    • 15.00.1395.012
    MicrosoftMicrosoft Exchange Server 2013 Cumulative Update 22
    • 15.00.0 – < 15.00.1473.006
    • 15.00.1473.006
    MicrosoftMicrosoft Exchange Server 2013 Cumulative Update 23
    • 15.00.0 – < 15.00.1497.012
    • 15.00.1497.012
    MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 10
    • 15.01.0 – < 15.01.1531.012
    • 15.01.1531.012
    MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 11
    • 15.01.0 – < 15.01.1591.018
    • 15.01.1591.018
    MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 12
    • 15.01.0 – < 15.01.1713.010
    • 15.01.1713.010
    MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 13
    • 15.01.0 – < 15.01.1779.008
    • 15.01.1779.008
    MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 14
    • 15.01.0 – < 15.01.1847.012
    • 15.01.1847.012
    MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 15
    • 15.01.0 – < 15.01.1913.012
    • 15.01.1913.012
    MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 16
    • 15.01.0 – < 15.01.1979.008
    • 15.01.1979.008
    MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 17
    • 15.01.0 – < 15.01.2044.013
    • 15.01.2044.013
    MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 18
    • 15.01.0 – < 15.01.2106.013
    • 15.01.2106.013
    MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 19
    • 15.01.0 – < 15.01.2176.009
    • 15.01.2176.009
    MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 8
    • 15.01.0 – < 15.01.1415.010
    • 15.01.1415.010
    MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 9
    • 15.01.0 – < 15.01.1466.016
    • 15.01.1466.016
    MicrosoftMicrosoft Exchange Server 2019
    • 15.02.0 – < 15.02.0221.018
    • 15.02.0221.018
    MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 1
    • 15.02.0 – < 15.01.1979.006
    • 15.01.1979.006
    MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 2
    • 15.02.0 – < 15.02.0397.011
    • 15.02.0397.011
    MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 3
    • 15.02.0 – < 15.02.0464.015
    • 15.02.0464.015
    MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 4
    • 15.02.0 – < 15.02.0659.012
    • 15.02.0659.012
    MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 5
    • 15.02.0 – < 15.02.0595.008
    • 15.02.0595.008
    MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 6
    • 15.02.0 – < 15.02.0529.013
    • 15.02.0529.013
    MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 7
    • 15.02.0 – < 15.02.0721.013
    • 15.02.0721.013
    MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 8
    • 15.02.0 – < 15.02.0792.010
    • 15.02.0792.010
    microsoftexchange_server
    • 2019
    • 2013
    • 2016
    • —
    • —
    • —

    Vendors and products

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    CISA KEV CatalogCISA Known Exploited Vulnerability (opens in a new tab)cisa.govactively exploited
    CSA/SingCERTActive Exploitation of Vulnerabilities in Microsoft Exchange Server (opens in a new tab)CSA/SingCERTactively exploited
    ANSSI / CERT-FRLicence Ouverte 2.0, as of CERTFR-2021-ALE-004 – [MàJ] Multiples vulnérabilités dans Microsoft Exchange Server (clôturée 2021-07-16) (opens in a new tab)cert.cyber.gouv.fractively exploited

    References & sources

    • portal.msrc.microsoft.comen-US/security-guidance/advisory/CVE-2021-26858x_refsource_MISC, x_transferred
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26858government-resource
    • Microsoft Security Update GuideMicrosoft Exchange Server Remote Code Execution VulnerabilityVendor advisory, Patch
    • cert.cyber.gouv.frANSSI / CERT-FR: CERTFR-2021-ALE-004 – [MàJ] Multiples vulnérabilités dans Microsoft Exchange Server (clôturée 2021-07-16)cert-fr

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. Record modifiedMicrosoft

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26858
      Referenceremoved
      https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26858
      —
      Reference typeremoved
      https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26858 Types: Patch, Vendor Advisory
      —

      Source identifier: secure@microsoft.com

    2. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: active, automatable: yes

      Show 5 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26858
      Referenceremoved
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26858
      —
      Reference typeremoved
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26858 Types: US Government Resource
      —
      SSVC assessmentremoved
      {"id":"CVE-2021-26858","role":"CISA Coordinator","options":[{"exploitation":"active"},{"automatable":"yes"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2021-03-01T00:00:00+00:00"}
      —
      SSVC assessmentadded
      —
      {"id":"CVE-2021-26858","role":"CISA Coordinator","options":[{"exploitation":"active"},{"automatable":"yes"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-08-12T03:55:36.937537Z"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    3. Record modifiedCVE Program

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26858
      Referenceremoved
      https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26858
      —
      Reference typeremoved
      https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26858 Types: Patch, Vendor Advisory
      —

      Source identifier: af854a3a-2127-422b-91ae-364da2661108

    4. Record modifiedMicrosoft

      Show 4 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26858
      Referenceremoved
      https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26858
      —
      Reference typeremoved
      https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26858 Types: Patch, Vendor Advisory
      —
      Affected versions (publisher)changed
      Microsoft Exchange Server 2019, Microsoft Exchange Server 2013 Cumulative Update 22, Microsoft Exchange Server 2019 Cumulative Update 2 (+21)
      Microsoft Exchange Server 2013 Cumulative Update 21, Microsoft Exchange Server 2013 Cumulative Update 22, Microsoft Exchange Server 2013 Cumulative Update 23 (+21)

      Source identifier: secure@microsoft.com

    Embed badge

    Show the severity and KEV status of this vulnerability on your site – with a link back here. The image is updated hourly.

    Badge preview for CVE-2021-26858
    <a href="https://intel.neosec.eu/en/cve/CVE-2021-26858"><img src="https://intel.neosec.eu/badge/cve/CVE-2021-26858.svg?lang=en" alt="CVE-2021-26858 – NEOSEC Intel" height="20"></a>