CVE-2026-67276: CVE-2026-67276: RouterOS does not compare the complete RSA public key when matching an SSH authentication …

What it is

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)

Exploitation evidence

First exploit evidence seen: 2026-09-06 (earliest date across the sources below).

Exploited in the wild

No source on this site lists in-the-wild exploitation yet (CISA KEV, VulnCheck KEV).

Public exploit code

GitHub proof-of-concept repositories

4 public repositories from 4 accounts, first seen 2026-09-06. Most starred: dinosn/mikrotrick-poc (101 stars), view repository.

Verify before running: public PoCs can be malicious. Read the code and only run it in an isolated lab. A PoC means exploit code is public, not that this CVE is exploited in the wild.

Sources: nomi-sec/PoC-in-GitHub.

How to fix it

Fixed versions

• mikrotik routeros: upgrade to 7.23.4 or later (affected from 7.9)
• mikrotik routeros: upgrade to 7.24.2 or later (affected from 7.24)

Derived from the NVD CPE configuration (versionEndExcluding / versionEndIncluding). Always confirm with the vendor advisory.

Vendor advisories and patches

• https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/ (Mitigation, Third Party Advisory)
• 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 (Release Notes)
• https://mikrotik.com/supportsec/september-2026-vulnerability/ (Vendor Advisory)

MITRE ATT&CK mitigations for this chain

• M1038 Execution Prevention (for T1553) : System settings can prevent applications from running that haven't been downloaded through the Apple Store (or other legitimate repositories) which can help mitigate some of these issues. Also enable application control solutions such as AppLocker and/or Device Guard to block the loading of malicious content.
• M1028 Operating System Configuration (for T1553) : Windows Group Policy can be used to manage root certificates and the <code>Flags</code> value of <code>HKLM\\SOFTWARE\\Policies\\Microsoft\\SystemCertificates\\Root\\ProtectedRoots</code> can be set to 1 to prevent non-administrator users from making further root installations into their own HKCU certificate store.
• M1026 Privileged Account Management (for T1553) : Manage the creation, modification, use, and permissions associated to privileged accounts, including SYSTEM and root.
• M1024 Restrict Registry Permissions (for T1553) : Ensure proper permissions are set for Registry hives to prevent users from modifying keys related to SIP and trust provider components. Components may still be able to be hijacked to suitable functions already present on disk if malicious modifications to Registry keys are not prevented.
• M1054 Software Configuration (for T1553) : HTTP Public Key Pinning (HPKP) is one method to mitigate potential [Adversary-in-the-Middle](https://attack.mitre.org/techniques/T1557) situations where and adversary uses a mis-issued or fraudulent certificate to intercept encrypted communications by enforcing use of an expected certificate.

Detection Generic guidance

Response checklist Generic guidance

1. Inventory: find every instance of the affected product and version (include internet-facing and forgotten ones).
2. Patch or mitigate per the vendor advisory; if you cannot patch, remove internet exposure or apply the vendor workaround.
3. Assume compromise if the system was exposed before patching: hunt for the indicators in the advisory and review logs back to the disclosure date.
4. Rotate credentials and secrets stored on or used by the affected system if compromise cannot be ruled out.