CriticalCVE-2025-3928

    Commvault Web Server unspecified vulnerability (CVE-2025-3928)

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

    What is affected, what to do

    The vulnerability in Commvault Web Server allows a remote, authenticated attacker to create and execute webshells, leading to full control over the affected systems. This vulnerability is actively exploited, as evidenced by its inclusion in the CISA KEV catalog on April 28, 2025. Affected versions include 11.36.45, 11.32.88, 11.28.140, and 11.20.216 on Windows and Linux platforms. An immediate update to versions 11.36.46, 11.32.89, 11.28.141, or 11.20.217 is urgently required to mitigate security risks.

    The vulnerability is being actively exploited; treat it as a priority. Update Commvault Web Server to version 11.36.46, Commvault Web Server to version 11.32.89, Commvault Web Server to version 11.28.141. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Commvault Web Server lt 11.36.0..11.36.46
    • Commvault Web Server lt 11.32.0..11.32.89
    • Commvault Web Server lt 11.28.0..11.28.141
    • Commvault Web Server lt 11.20.0..11.20.217
    Fixed in
    • Commvault Web Server 11.36.46
    • Commvault Web Server 11.32.89
    • Commvault Web Server 11.28.141
    • Commvault Web Server 11.20.217

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

    Metrics

    8.8

    Priority

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

    Source: NVD, CVSS v3

    8.8

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: SingCERT, CVE.org, pwn.watch

    2.5 %

    EPSS score

    Moderate — model estimates 1-10% exploitation likelihood.

    Source: FIRST EPSS, percentile 84.9

    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
    210.33 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: VulnCheck KEV (opens in a new tab), 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
    8.8 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
    8.8
    CVSS v4

    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
    8.7
    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
    2.5 %
    Moderate — model estimates 1-10% exploitation likelihood.
    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
    84.9
    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 · not automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 30 April 2025
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-94

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This flaw is network-reachable with low complexity and needs only a low-privileged account. From there, a webshell gives the attacker full impact on the confidentiality, integrity and availability of the web server. Backup platforms are high-value targets because they concentrate privileged credentials for nearly every system and cloud tenant, and compromising them undermines recovery. That makes this a classic pre-positioning step for extortion even though CISA does not flag known ransomware use. Exploitation likelihood is elevated. Organisations with an internet-exposed Commvault console or Commvault-backed SaaS/cloud backup should treat this as critical and patch within 24 h. Internal-only, segmented deployments still warrant high priority in the next emergency patch window.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Patch now: Upgrade every Commvault Web Server and CommServe instance (Windows and Linux) to at least the fixed build for its release branch: 11.36.46, 11.32.89, 11.28.141 or 11.20.217. Verify the installed build in the Commvault console. Treat any host below these builds as potentially compromised.
      • Cut exposure: Until patched, move internet-facing Commvault Web Server and Command Center interfaces behind VPN or an access proxy. Restrict perimeter firewall rules to known admin networks.
      • Hunt before you patch: Check the Commvault web server webroots (IIS or Tomcat under the Commvault install path) for newly created or modified .aspx, .ashx, .asmx, .jsp and .jspx files. Preserve any artefacts forensically (hash, timestamps, copy) before removal.
      • Rotate credentials: Exploitation requires authentication, so reset all Commvault console accounts and service accounts. Also rotate every credential stored in Commvault for cloud and SaaS backup targets (client secrets, storage keys). Disable stale accounts.
      • Escalate on findings: If you find a webshell, isolate the host and validate backup integrity (immutable and air-gapped copies). Assess the NIS2 early-warning obligation (24 h).

    2. Runbook step 2

      Mitigation layers

      • Network segmentation: Place backup infrastructure (CommServe, MediaAgents, Web Server) in a dedicated management zone. Allow inbound traffic only from admin jump hosts. Default-deny outbound internet traffic from the web server to break webshell callbacks and exfiltration.
      • WAF/reverse proxy: Block requests to executable script extensions outside known Commvault paths (rule idea: deny POST to *.aspx|*.jsp not on an allowlist). Alert on unusually large multipart/form-data uploads to the console.
      • Endpoint hardening: Use EDR or ASR rules to stop the web server process (w3wp.exe, tomcat*.exe, java) from spawning shells (cmd.exe, powershell.exe, sh, bash). Remove the web service account's write access to the webroot where operationally possible.
      • IAM/least privilege: Enforce MFA on all Commvault console access and keep Master/admin roles to a minimal group. Never run the Commvault web server under domain-admin-equivalent service accounts.
      • Configuration: Disable unused web components and console entry points. Apply IP-based restrictions at the web server layer (IIS IP Restrictions or Tomcat RemoteAddrValve).

    3. Runbook step 3

      Detection rules

      • Sysmon EID 11 (FileCreate): New script files in the Commvault webroot written by w3wp.exe or java.exe. KQL: DeviceFileEvents | where FolderPath has "Commvault" and FileName matches regex @"\.(aspx|ashx|asmx|jsp|jspx)$" and InitiatingProcessFileName in~ ("w3wp.exe","java.exe","tomcat9.exe")
      • Sysmon EID 1 / EDR process ancestry: Web server process parenting cmd.exe, powershell.exe, whoami.exe, net.exe, nltest.exe or certutil.exe. Sigma shape: ParentImage|endswith: ['\w3wp.exe','\java.exe'] AND Image|endswith: ['\cmd.exe','\powershell.exe','\whoami.exe']
      • Linux auditd: execve events whose ppid is the Tomcat/Java process with exe=/bin/sh|/bin/bash|/usr/bin/curl|/usr/bin/wget. Add a watch (-w <webroot> -p wa) on the Commvault webroot.
      • Web server access logs (IIS/Tomcat): First-seen .aspx/.jsp URI paths followed by repeated POST requests from the same source IP. Also flag console access from unfamiliar ranges or off-hours. Correlate successful logons (Windows EID 4624, Commvault audit trail) from new source IPs.
      • Network telemetry (Zeek/Suricata): Outbound connections from the Commvault web server to destinations other than Commvault update sources or known cloud storage endpoints. Review abnormal upload volumes to cloud storage as possible 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

    Commvault Web Server has an unspecified vulnerability that can be exploited by a remote, authenticated attacker. According to the Commvault advisory: "Webservers can be compromised through bad actors creating and executing webshells." Fixed in version 11.36.46, 11.32.89, 11.28.141, and 11.20.217 for Windows and Linux platforms. This vulnerability was added to the CISA Known Exploited Vulnerabilities (KEV) Catalog on 2025-04-28.

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

    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
    CommvaultWeb Server
    • 11.28.0 – < 11.28.141
    • 11.32.0 – < 11.32.89
    • 11.20.0 – < 11.20.217
    • 11.36.0 – < 11.36.46
    • 11.28.141
    • 11.32.89
    • 11.20.217
    • 11.36.46
    commvaultcommvault
    • 11.36.0 – < 11.36.46
    • 11.28.0 – < 11.28.141
    • 11.32.0 – < 11.32.89
    • 11.20.0 – < 11.20.217
    • 11.36.46
    • 11.28.141
    • 11.32.89
    • 11.20.217

    Vendors and products

    Weakness classes (CWE)

    • CWE-94Improper Control of Generation of Code ('Code Injection')

      Base

      The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.

      Entry at MITRE CWE-94

    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 High-Severity Vulnerability in Commvault Software (opens in a new tab)CSA/SingCERTactively exploited

    References & sources

    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. NVD analysis modifiedNVD

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Reference typechanged
      Cybersecurity and Infrastructure Security Agency (CISA) U.S. Civilian Government: https://www.commvault.com/blogs/notice-security-advisory-update Types: Vendor Advisory
      Cybersecurity and Infrastructure Security Agency (CISA) U.S. Civilian Government: https://www.commvault.com/blogs/notice-security-advisory-update Types: Broken Link, Vendor Advisory

      Source identifier: nvd@nist.gov

    2. Record modified9119a7d8…

      Show 18 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://documentation.commvault.com/securityadvisories/CV_2025_03_1.html
      Referenceadded
      —
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2025-3928
      Referenceadded
      —
      https://www.cisa.gov/news-events/alerts/2025/05/22/advisory-update-cyber-threat-activity-targeting-commvaults-saas-cloud-application-metallic
      Referenceadded
      —
      https://www.commvault.com/blogs/customer-security-update
      Referenceadded
      —
      https://www.commvault.com/blogs/notice-security-advisory-update
      Referenceadded
      —
      https://www.commvault.com/blogs/security-advisory-march-7-2025
      Referenceremoved
      https://documentation.commvault.com/securityadvisories/CV_2025_03_1.html
      —
      Referenceremoved
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2025-3928
      —
      Referenceremoved
      https://www.cisa.gov/news-events/alerts/2025/05/22/advisory-update-cyber-threat-activity-targeting-commvaults-saas-cloud-application-metallic
      —
      Referenceremoved
      https://www.commvault.com/blogs/customer-security-update
      —
      Referenceremoved
      https://www.commvault.com/blogs/notice-security-advisory-update
      —
      Referenceremoved
      https://www.commvault.com/blogs/security-advisory-march-7-2025
      —
      Reference typeremoved
      https://documentation.commvault.com/securityadvisories/CV_2025_03_1.html Types: Vendor Advisory
      —
      Reference typeremoved
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2025-3928 Types: Third Party Advisory, US Government Resource
      —
      Reference typeremoved
      https://www.cisa.gov/news-events/alerts/2025/05/22/advisory-update-cyber-threat-activity-targeting-commvaults-saas-cloud-application-metallic Types: Third Party Advisory, US Government Resource
      —
      Reference typeremoved
      https://www.commvault.com/blogs/customer-security-update Types: Vendor Advisory
      —
      Reference typeremoved
      https://www.commvault.com/blogs/notice-security-advisory-update Types: Vendor Advisory
      —
      Reference typeremoved
      https://www.commvault.com/blogs/security-advisory-march-7-2025 Types: Vendor Advisory
      —

      Source identifier: 9119a7d8-5eab-497f-8521-727c672e3725

    3. Record modifiedCISA ADP

      Weakness type: CWE-94

      Show 4 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-94
      Referenceadded
      —
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-3928
      Referenceremoved
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-3928
      —
      Reference typeremoved
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-3928 Types: US Government Resource
      —

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

    4. Record modifiedCVE Program

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://www.bleepingcomputer.com/news/security/commvault-says-recent-breach-didnt-impact-customer-backup-data/
      Referenceremoved
      https://www.bleepingcomputer.com/news/security/commvault-says-recent-breach-didnt-impact-customer-backup-data/
      —
      Reference typeremoved
      https://www.bleepingcomputer.com/news/security/commvault-says-recent-breach-didnt-impact-customer-backup-data/ Types: Third Party Advisory
      —

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

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