CVE-2026-67276
SSH user impersonation possible in Mikrotik RouterOS
CRITICAL 9.2EPSS 6.5%
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)
- Affected
- Mikrotik · RouterOS
- CVSS v4.0 CERT
- 9.2 CRITICAL
CVSS:4.0/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 - CVSS v3.1 NVD
- 8.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS
- 6.45% chance of exploitation in the next 30 days, 94th percentile
- Published
- 2026-09-05
- Updated
- 2026-09-09
Proof-of-concept exploits (6)
- https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldn…
- BlackHatExploitation/exploit-mikrotik-202610★ · 2026-09-07
- HORKimhab/CVE-2026-672761★ · 2026-09-07
- 4rt-Net/Mikrotrick_POC1★ · 2026-09-09
- gagaltotal/CVE-2026-mikrotik-poc3★ · 2026-10-08
- HackSpeak/CVE-2026-672794★ · 2026-09-26
Security advisories
- https://mikrotik.com/supportsec/september-2026-vulnerability
- https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve
- https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited
- https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldn…
- https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801
- https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800