CriticalCVE-2026-67276

    RouterOS: Improper Verification of Cryptographic Signature (CVE-2026-67276)

    Published Last modified Sources: BSI

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    What is affected, what to do

    RouterOS does not compare the complete RSA public key when matching an SSH authentication request to an authorized user key, checking the key type and modulus but omitting the exponent. Because signature verification uses the client-supplied key, an attacker knowing an authorized RSA modulus can supply a key with exponent one, forge a valid signature, and open an SSH command channel as the target user without the private key.This issue affects only 7.x branch was fixed in versions: 7.23.4 (Long-term) and 7.24.2 (Stable)

    The vulnerability is being actively exploited; treat it as a priority. Update Mikrotik RouterOS to version 7.24.2, Mikrotik RouterOS to version 7.23.4.

    Affected
    • Mikrotik RouterOS lt 7.24..7.24.2
    • Mikrotik RouterOS lt 7.9..7.23.4
    Fixed in
    • Mikrotik RouterOS 7.24.2
    • Mikrotik RouterOS 7.23.4

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

    Metrics

    9.2

    Priority

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

    Source: Vendor (CNA), CVSS v4

    8.1

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: BSI

    8.9 %

    EPSS score

    Moderate — model estimates 1-10% exploitation likelihood.

    Source: FIRST EPSS, percentile 95.3

    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
    119.66 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) 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
    9.2 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
    8.1
    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
    9.2
    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
    8.9 %
    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
    95.3
    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
    —
    Published
    CISA assessment (SSVC)
    Exploitation: none known · not automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 8 September 2026
    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-347

    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

    RouterOS does not compare the complete RSA public key when matching an SSH authentication request to an authorized user key, checking the key type and modulus but omitting the exponent. Because signature verification uses the client-supplied key, an attacker knowing an authorized RSA modulus can supply a key with exponent one, forge a valid signature, and open an SSH command channel as the target user without the private key.This issue affects only 7.x branch was fixed in versions: 7.23.4 (Long-term) and 7.24.2 (Stable)

    Source: BSI WID Portal

    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
    MikrotikRouterOS
    • 6.0.0 – < 6.49.21
    • 7.0.0 – < 7.23.4
    • 7.0.0 – < 7.23.6
    • 7.20 – < 7.23.4
    • 7.24 – < 7.24.2
    • 7.24 – < 7.24.3
    • 7.9 – < 7.23.4
    • 6.49.21
    • 7.23.4
    • 7.23.6
    • 7.23.4
    • 7.24.2
    • 7.24.3
    • 7.23.4
    MikroTikRouterOS
    • < 6.49.21
    • < 7.23.4
    • < 7.24.2
    • <7.25 beta 3
    • 6.49.21
    • 7.23.4
    • 7.24.2
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Othermikrotikrouteros—

    Weakness classes (CWE)

    • CWE-347Improper Verification of Cryptographic Signature

      Base

      The product does not verify, or incorrectly verifies, the cryptographic signature for data.

      Entry at MITRE CWE-347

    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
    PoC-in-GitHub (nomi-sec)Mikrotrick_POC (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)CVE-2026-67276 (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)exploit-mikrotik-2026 (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)mikrotrick-poc (opens in a new tab)github.comPoC (publicly reported)reported, not verified

    References & sources

    • cert.plen/posts/2026/09/mikrotik-routeros-cveeuvd, Third-party advisory
    • cert.plen/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-…euvd, Technical description
    • npratley.netreversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-w…euvd, Exploit
    • mikrotik.comsupportsec/september-2026-vulnerabilityeuvd, Vendor advisory
    • forum.mikrotik.comt/7-23-4-long-term-is-released/272801euvd, Release notes
    • forum.mikrotik.comt/7-24-2-stable-is-released/272800euvd, Release notes
    • forum.mikrotik.comt/6-49-21-long-term-is-released/272802euvd, Release notes
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2026-86060government-resource
    • pwn.watchpwn.watch: MikroTik RouterOS: MikroTik RouterOS Improper Neutralization of Argument Delimiters in a Command Vulnerabilitypwn-watch
    • mikrotik.comMikroTik RouterOS — CVE-2026-86060pwn-watch
    • NVD (NIST)NVD: CVE-2026-86060pwn-watch
    • NVD (NIST)NVD: CVE-2026-67277pwn-watch
    • NVD (NIST)NVD: CVE-2026-67279pwn-watch
    • cisa.govCISA Known Exploited Vulnerabilities Catalogpwn-watch
    • forum.mikrotik.comt/7-23-6-long-term-is-released/273139euvd, Release notes
    • forum.mikrotik.comt/7-24-3-stable-is-released/273138euvd, Release notes
    • bishopfox.comblog/mikrotrick-inside-the-routeros-takeover-chainThird-party advisory
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2026-67279government-resource
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2026-67277government-resource

    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. Initial analysis by NVDNVD

      Newly listed as affected:

      CVSS V3.1: AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

      Show 8 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      CVSSadded
      —
      AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
      Product configurationadded
      —
      OR *cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:* versions from (including) 7.24 up to (excluding) 7.24.2 *cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:* versions from (including) 7.9 up to (excluding) 7.23.4
      Reference typeadded
      —
      CERT.PL: https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve Types: Third Party Advisory
      Reference typeadded
      —
      CERT.PL: https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/ Types: Mitigation, Third Party Advisory
      Reference typeadded
      —
      CERT.PL: https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801 Types: Release Notes
      Reference typeadded
      —
      CERT.PL: https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800 Types: Release Notes
      Reference typeadded
      —
      CERT.PL: https://mikrotik.com/supportsec/september-2026-vulnerability/ Types: Vendor Advisory
      Reference typeadded
      —
      CERT.PL: https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/ Types: Exploit, Third Party Advisory

      Source identifier: nvd@nist.gov

    2. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: no

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentchanged
      {"id":"CVE-2026-67276","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-09-08T14:48:45.722509Z"}
      {"id":"CVE-2026-67276","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-09-08T00:00:00+00:00"}

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

    3. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: no

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
      —
      {"id":"CVE-2026-67276","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-09-08T14:48:45.722509Z"}

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

    4. Record modifiedcert.pl

      Description added or changed

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionchanged
      RouterOS does not compare the complete RSA public key when matching an SSH authentication request to an authorized user key, checking the key type and modulus but omitting the exponent. Because signature verification uses the client-supplied key, an attacker knowing an authorized RSA modulus can supply a key with exponent one, forge a valid signature, and open an SSH command channel as the target user without the private key.This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)
      RouterOS does not compare the complete RSA public key when matching an SSH authentication request to an authorized user key, checking the key type and modulus but omitting the exponent. Because signature verification uses the client-supplied key, an attacker knowing an authorized RSA modulus can supply a key with exponent one, forge a valid signature, and open an SSH command channel as the target user without the private key.This issue affects only 7.x branch was fixed in versions: 7.23.4 (Long-term) and 7.24.2 (Stable)
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/67xxx/CVE-2026-67276.json">CVE-2026-67276</a>
      Referenceremoved
      https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802
      —

      Source identifier: cvd@cert.pl

    5. Record modifiedcert.pl

      Description added or changed

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionchanged
      RouterOS does not compare the complete RSA public key when matching an SSH authentication request to an authorized user key, checking the key type and modulus but omitting the exponent. Because signature verification uses the client-supplied key, an attacker knowing an authorized RSA modulus can supply a key with exponent one, forge a valid signature, and open an SSH command channel as the target user without the private key.This issue was fixed in versions: 6.49.21 (Lont-term), 7.23.4 (Lont-term) and 7.24.2 (Stable)
      RouterOS does not compare the complete RSA public key when matching an SSH authentication request to an authorized user key, checking the key type and modulus but omitting the exponent. Because signature verification uses the client-supplied key, an attacker knowing an authorized RSA modulus can supply a key with exponent one, forge a valid signature, and open an SSH command channel as the target user without the private key.This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)

      Source identifier: cvd@cert.pl

    Show one older change

    1. Receivedcert.pl

      CVSS V4.0: AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

      Weakness type: CWE-347

      Description added or changed

      Show 11 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      RouterOS does not compare the complete RSA public key when matching an SSH authentication request to an authorized user key, checking the key type and modulus but omitting the exponent. Because signature verification uses the client-supplied key, an attacker knowing an authorized RSA modulus can supply a key with exponent one, forge a valid signature, and open an SSH command channel as the target user without the private key.This issue was fixed in versions: 6.49.21 (Lont-term), 7.23.4 (Lont-term) and 7.24.2 (Stable)
      CVSSadded
      —
      AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
      Weakness type (CWE)added
      —
      CWE-347
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/67xxx/CVE-2026-67276.json">CVE-2026-67276</a>
      Referenceadded
      —
      https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve
      Referenceadded
      —
      https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/
      Referenceadded
      —
      https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802
      Referenceadded
      —
      https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801
      Referenceadded
      —
      https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800
      Referenceadded
      —
      https://mikrotik.com/supportsec/september-2026-vulnerability/
      Referenceadded
      —
      https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/

      Source identifier: cvd@cert.pl

    Linked CVEs

    Linked CVEs
    CriticalCVE-2026-86060SSH session privilege manipulation via a crafted username in Mikrotik RouterOS9.8Actively exploited
    HighCVE-2026-67281Unauthenticated file read in Mikrotik RouterOS7.5—
    CriticalCVE-2026-67279SSH Pre-Authentication Rekey State Bypass in MikroTik RouterOS6.5Actively exploited
    CriticalCVE-2026-67278TLS server impersonation possible in Mikrotik RouterOS9.1—
    CriticalCVE-2026-67277Kernel memory disclosure and denial of service in MikroTik RouterOS btest service8.2Actively exploited
    CriticalCVE-2026-67276SSH user impersonation possible in Mikrotik RouterOS8.1—

    Linked advisories

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    Badge preview for CVE-2026-67276
    <a href="https://intel.neosec.eu/en/cve/CVE-2026-67276"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-67276.svg?lang=en" alt="CVE-2026-67276 – NEOSEC Intel" height="20"></a>