Intel

CVE-2026-67276

MikroTik RouterOS: Improper Verification of Cryptographic Signature

criticalPoCEPSS 6.5%

Affected

  • MikroTik/RouterOS < *..6.49.21
  • MikroTik/RouterOS < *..7.23.4
  • MikroTik/RouterOS < *..7.24.2
  • MikroTik/RouterOS range_unparsed *..<7.25 beta 3

Fixed in

  • MikroTik/RouterOS 6.49.21
  • MikroTik/RouterOS 7.23.4
  • MikroTik/RouterOS 7.24.2

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: NVD (NIST)cvelistv5ENISA EUVDBSI CSAFBSI WID Portal

Affected operating systems

  • other

    mikrotik / routeros

Metrics

XIEM Effective CVSS
9.2
Source: cna-v4
EPSS percentile
93.6 %
Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
KEV status
—
Show all metrics
Severity
critical
Priority score
145.04
Exploit maturity
PoC (publicly reported)
CVSS v3
8.1
CVSS v4
9.2
EPSS score
6.5 %
Moderate — model estimates 1-10% exploitation likelihood.
Published
2026-09-05 20:00 UTC
CWE
CWE-347

Weakness classes (CWE)

  • CWE-347Base

    Improper Verification of Cryptographic Signature

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

    cwe.mitre.org →

References & sources

Reanalysis & status changes

Chronological NVD audit events for this CVE — reanalyses, CVSS updates, CPE diffs.

  1. Initial Analysis2026-09-25 14:57 UTC· nvd@nist.gov
    • CVSS V3.1: AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
    • CPE Configuration: 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 Type: CERT.PL: https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve Types: Third Party Advisory
    • Reference Type: CERT.PL: https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/ Types: Mitigation, Third Party Advisory
  2. CVE Modified2026-09-09 05:17 UTC· 134c704f-9b21-4f2e-91b3-4a467353bcc0
    • SSVC: {"id":"CVE-2026-67276","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalI… → {"id":"CVE-2026-67276","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalI…
  3. CVE Modified2026-09-08 15:18 UTC· 134c704f-9b21-4f2e-91b3-4a467353bcc0
    • SSVC: {"id":"CVE-2026-67276","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalI…
  4. CVE Modified2026-09-07 14:16 UTC· cvd@cert.pl
    • 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 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: Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/67xxx/CVE-2026-67276.json">CVE-2026-67276</a>
    • Reference: https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802
  5. CVE Modified2026-09-05 21:16 UTC· cvd@cert.pl
    • 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 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)

Linked advisories