CVE-2026-67276 SSH user impersonation possible in Mikrotik RouterOS

Critical 9.2 Published 5 Sep 2026 Updated 9 Sep 2026

Attackers can impersonate SSH users by forging signatures using a modified RSA key, bypassing authentication to execute commands as the target user.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-67276?

CVE-2026-67276 is a critical authentication bypass vulnerability in Mikrotik Routeros, published on 5 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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)

Weakness: CWE-347

Which versions are affected by CVE-2026-67276?

It affects 1 product.

Products include Mikrotik Routeros.

How do I fix CVE-2026-67276?

No fix has been published for CVE-2026-67276 yet. Limit exposure of the affected software until one is available.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2026-67276 being exploited?

There is no known exploitation of CVE-2026-67276 in the wild and no public exploit code.

Public exploit code: 4 proofs of concept on GitHub.

All Mikrotik Routeros vulnerabilities

Sources

Also known as GHSA-j9wg-77fw-f22f.