9.1
CRITICAL
CVSS 3.1
CVE-2026-67278
TLS server impersonation possible in Mikrotik RouterOS
Overview
Description
MikroTik RouterOS accepts malformed RSA/PKCS#1 v1.5 signatures across RSA-based services, including TLS/X.509 certificate validation and SSH host-key authentication. Because its trust store includes an e=3 root CA, an attacker controlling or redirecting an outbound RouterOS TLS connection can use the root’s public certificate - without its private key - to forge a trusted intermediate and issue certificates for arbitrary hostnames, enabling TLS server impersonation. The same permissive verification also undermines RSA-based SSH authentication. This issue affects only 7.x branch was fixed in versions: 7.23.6 (Long-term) and 7.24.3 (Stable). Releases 7.23.4 and 7.24.2 included an incomplete fix.
Details
INFO
Published Date :
Sept. 5, 2026, 8:17 p.m.
Last Modified :
Sept. 25, 2026, 2:56 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework
for assessing the severity of vulnerabilities in software and systems.
We collect and displays CVSS scores from various sources for each CVE.
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | CRITICAL | [email protected] | ||||
| CVSS 4.0 | MEDIUM | 4bb8329e-dd38-46c1-aafb-9bf32bcb93c6 | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
Update MikroTik RouterOS to a fixed version to address RSA signature validation vulnerability.
- Update RouterOS to 6.49.21 or later.
- Update RouterOS to 7.23.4 or later.
- Update RouterOS to 7.24.2 or later.
References
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-67278.
| URL | Resource |
|---|---|
| https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve | Third Party Advisory |
| https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/ | Mitigation Third Party Advisory |
| https://forum.mikrotik.com/t/7-23-6-long-term-is-released/273139 | Release Notes |
| https://forum.mikrotik.com/t/7-24-3-stable-is-released/273138 | Release Notes |
| https://mikrotik.com/supportsec/september-2026-vulnerability/ | Vendor Advisory |
| https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/ | Exploit Third Party Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-67278 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-67278
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-67278 vulnerability anywhere in the article.
-
cert.pl
Vulnerabilities in Mikrotik RouterOS software
Vulnerabilities in Mikrotik RouterOS software CVE ID CVE-2026-67276 Publication date 05 September 2026 Vendor Mikrotik Product RouterOS Vulnerable versions From 7.24 below 7.24.2From 7.0.0 below 7.23. ... Read more
Published Date:
Sep 05, 2026 (1 month ago)
The following table lists the changes that have been made to the
CVE-2026-67278 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Sep. 25, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Added CPE Configuration OR *cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:* versions from (including) 7.0 up to (excluding) 7.23.6 *cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:* versions from (including) 7.24 up to (excluding) 7.24.3 Added Reference Type CERT.PL: https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve Types: Third Party Advisory Added Reference Type CERT.PL: https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/ Types: Mitigation, Third Party Advisory Added Reference Type CERT.PL: https://forum.mikrotik.com/t/7-23-6-long-term-is-released/273139 Types: Release Notes Added Reference Type CERT.PL: https://forum.mikrotik.com/t/7-24-3-stable-is-released/273138 Types: Release Notes Added Reference Type CERT.PL: https://mikrotik.com/supportsec/september-2026-vulnerability/ Types: Vendor Advisory Added Reference Type CERT.PL: https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/ Types: Exploit, Third Party Advisory -
CVE Modified by [email protected]
Sep. 17, 2026
Action Type Old Value New Value Changed Description MikroTik RouterOS accepts malformed RSA/PKCS#1 v1.5 signatures across RSA-based services, including TLS/X.509 certificate validation and SSH host-key authentication. Because its trust store includes an e=3 root CA, an attacker controlling or redirecting an outbound RouterOS TLS connection can use the root’s public certificate - without its private key - to forge a trusted intermediate and issue certificates for arbitrary hostnames, enabling TLS server impersonation. The same permissive verification also undermines RSA-based SSH authentication. This issue affects only 7.x branch was fixed in versions: 7.23.6 (Long-term) and 7.24.3 (Stable) Releases 7.23.4 and 7.24.2 included an incomplete fix. MikroTik RouterOS accepts malformed RSA/PKCS#1 v1.5 signatures across RSA-based services, including TLS/X.509 certificate validation and SSH host-key authentication. Because its trust store includes an e=3 root CA, an attacker controlling or redirecting an outbound RouterOS TLS connection can use the root’s public certificate - without its private key - to forge a trusted intermediate and issue certificates for arbitrary hostnames, enabling TLS server impersonation. The same permissive verification also undermines RSA-based SSH authentication. This issue affects only 7.x branch was fixed in versions: 7.23.6 (Long-term) and 7.24.3 (Stable). Releases 7.23.4 and 7.24.2 included an incomplete fix. -
CVE Modified by [email protected]
Sep. 17, 2026
Action Type Old Value New Value Changed Description MikroTik RouterOS accepts malformed RSA/PKCS#1 v1.5 signatures during X.509 validation. Because its trust store includes an e=3 root CA, an attacker controlling or redirecting an outbound RouterOS TLS connection can use the root’s public certificate - without its private key - to forge a trusted intermediate and issue certificates for arbitrary hostnames, enabling TLS server impersonation. This issue affects only 7.x branch was fixed in versions: 7.23.4 (Long-term) and 7.24.2 (Stable) MikroTik RouterOS accepts malformed RSA/PKCS#1 v1.5 signatures across RSA-based services, including TLS/X.509 certificate validation and SSH host-key authentication. Because its trust store includes an e=3 root CA, an attacker controlling or redirecting an outbound RouterOS TLS connection can use the root’s public certificate - without its private key - to forge a trusted intermediate and issue certificates for arbitrary hostnames, enabling TLS server impersonation. The same permissive verification also undermines RSA-based SSH authentication. This issue affects only 7.x branch was fixed in versions: 7.23.6 (Long-term) and 7.24.3 (Stable) Releases 7.23.4 and 7.24.2 included an incomplete fix. Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/67xxx/CVE-2026-67278.json">CVE-2026-67278</a> Added Reference https://forum.mikrotik.com/t/7-23-6-long-term-is-released/273139 Added Reference https://forum.mikrotik.com/t/7-24-3-stable-is-released/273138 Removed Reference https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801 Removed Reference https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800 -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Sep. 08, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-67278', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-09-08T15:30:45.430794Z'} -
CVE Modified by [email protected]
Sep. 07, 2026
Action Type Old Value New Value Changed Description MikroTik RouterOS accepts malformed RSA/PKCS#1 v1.5 signatures during X.509 validation. Because its trust store includes an e=3 root CA, an attacker controlling or redirecting an outbound RouterOS TLS connection can use the root’s public certificate - without its private key - to forge a trusted intermediate and issue certificates for arbitrary hostnames, enabling TLS server impersonation. This issue was fixed in versions: 7.23.4 (Long-term) and 7.24.2 (Stable) MikroTik RouterOS accepts malformed RSA/PKCS#1 v1.5 signatures during X.509 validation. Because its trust store includes an e=3 root CA, an attacker controlling or redirecting an outbound RouterOS TLS connection can use the root’s public certificate - without its private key - to forge a trusted intermediate and issue certificates for arbitrary hostnames, enabling TLS server impersonation. This issue affects only 7.x branch was fixed in versions: 7.23.4 (Long-term) and 7.24.2 (Stable) -
CVE Modified by [email protected]
Sep. 07, 2026
Action Type Old Value New Value Changed Description MikroTik RouterOS accepts malformed RSA/PKCS#1 v1.5 signatures during X.509 validation. Because its trust store includes an e=3 root CA, an attacker controlling or redirecting an outbound RouterOS TLS connection can use the root’s public certificate - without its private key - to forge a trusted intermediate and issue certificates for arbitrary hostnames, enabling TLS server impersonation. This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable) MikroTik RouterOS accepts malformed RSA/PKCS#1 v1.5 signatures during X.509 validation. Because its trust store includes an e=3 root CA, an attacker controlling or redirecting an outbound RouterOS TLS connection can use the root’s public certificate - without its private key - to forge a trusted intermediate and issue certificates for arbitrary hostnames, enabling TLS server impersonation. This issue was fixed in versions: 7.23.4 (Long-term) and 7.24.2 (Stable) Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/67xxx/CVE-2026-67278.json">CVE-2026-67278</a> Removed Reference https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802 -
CVE Modified by [email protected]
Sep. 05, 2026
Action Type Old Value New Value Changed Description MikroTik RouterOS accepts malformed RSA/PKCS#1 v1.5 signatures during X.509 validation. Because its trust store includes an e=3 root CA, an attacker controlling or redirecting an outbound RouterOS TLS connection can use the root’s public certificate - without its private key - to forge a trusted intermediate and issue certificates for arbitrary hostnames, enabling TLS server impersonation. This issue was fixed in versions: 6.49.21 (Lont-term), 7.23.4 (Lont-term) and 7.24.2 (Stable) MikroTik RouterOS accepts malformed RSA/PKCS#1 v1.5 signatures during X.509 validation. Because its trust store includes an e=3 root CA, an attacker controlling or redirecting an outbound RouterOS TLS connection can use the root’s public certificate - without its private key - to forge a trusted intermediate and issue certificates for arbitrary hostnames, enabling TLS server impersonation. This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable) -
New CVE Received by [email protected]
Sep. 05, 2026
Action Type Old Value New Value Added Description MikroTik RouterOS accepts malformed RSA/PKCS#1 v1.5 signatures during X.509 validation. Because its trust store includes an e=3 root CA, an attacker controlling or redirecting an outbound RouterOS TLS connection can use the root’s public certificate - without its private key - to forge a trusted intermediate and issue certificates for arbitrary hostnames, enabling TLS server impersonation. This issue was fixed in versions: 6.49.21 (Lont-term), 7.23.4 (Lont-term) and 7.24.2 (Stable) Added CVSS V4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/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 Added CWE CWE-347 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/67xxx/CVE-2026-67278.json">CVE-2026-67278</a> Added Reference https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve Added Reference https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/ Added Reference https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802 Added Reference https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801 Added Reference https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800 Added Reference https://mikrotik.com/supportsec/september-2026-vulnerability/ Added Reference https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/
EPSS is a daily estimate of the probability of exploitation activity
being observed over the next 30 days. Following chart shows the EPSS
score history of the vulnerability.