Vulnerability in Mikrotik Routeros
CVE-2026-67276
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)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.065 (93.7th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 94th percentile — 93.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.065 · change: +0.062
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- cert.pl/en/posts/2026/09/mikrotik-routeros-cve (Third Party Advisory, third-party-advisory)
- cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploite… (technical-description, Third Party Advisory, Mitigation)
- forum.mikrotik.com/t/6-49-21-long-term-is-released/272802 (release-notes)
- forum.mikrotik.com/t/7-23-4-long-term-is-released/272801 (release-notes, Release Notes)
- forum.mikrotik.com/t/7-24-2-stable-is-released/272800 (release-notes, Release Notes)
- mikrotik.com/supportsec/september-2026-vulnerability/ (vendor-advisory, Vendor Advisory)
- npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-woul… (Exploit, Third Party Advisory, exploit)
Frequently asked questions
- What is CVE-2026-67276?
- CVE-2026-67276 is a high-severity vulnerability in Mikrotik Routeros, classified under Improper Verification of Cryptographic Signature. CVSS score: 8.1/10. Published 2026-09-05.
- How severe is CVE-2026-67276?
- High severity. CVSS v3 base score is 8.1 out of 10.
- Is CVE-2026-67276 known to be exploited?
- 4 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.