High severity · published Sep 5, 2026
CVE-2026-67276
SSH user impersonation possible in Mikrotik RouterOS
8.1
CVSS
8.9%
EPSS
No
On KEV
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)
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)8.9% · higher than 95% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RO
RouterOS · Mikrotik
7.24 before 7.24.2; 7.9 before 7.23.4 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-67276
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-67276
Third Party Advisory
https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve
Mitigation
https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/
Release Notes
https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801
Release Notes
https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800
Vendor Advisory
https://mikrotik.com/supportsec/september-2026-vulnerability/
Exploit
https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/
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