Threat Intelligence / CVE / CVE-2026-67278

CVE-2026-67278 — Mikrotik RouterOS

CVSS v4.0 6.3 (Medium, derived from score) · EPSS 0.1% (higher than 6.2% of all scored CVEs) · Priority 5.4/10 · Published 2026-09-05

As of 2026-09-05, CVE-2026-67278 is a Medium-severity (band derived from the CVSS v4.0 score, not stated by the CNA) vulnerability in Mikrotik RouterOS, CVSS v4.0 6.3, EPSS 0.1% (6.2th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-67278, most recently “Attackers Hijack MikroTik Routers Through Internet-Exposed SSH Without Authentication (MikroTrick)”.

Last updated: 2026-09-05

What is CVE-2026-67278?

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)

The record classifies CVE-2026-67278 under weakness class CWE-347. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 13 days ago.

Severity and exploitation probability

CVSS v4.0 base score
6.3 — Medium (derived from score)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
EPSS (FIRST)
0.1% probability of exploitation in the next 30 days, higher than 6.2% of all scored CVEs
CISA KEV
Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority
5.4/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published
2026-09-05

Is CVE-2026-67278 being exploited?

Weaponised exploit code for CVE-2026-67278 is publicly available. 1 public proof-of-concept repository is tracked for this identifier. It currently carries a trending score of 39 in the Threadlinqs vulnerability feed.

Affected products and versions

How to fix CVE-2026-67278

No vendor patch reference has been recorded for CVE-2026-67278 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

Threat activity tracking CVE-2026-67278

1 tracked threat in the Threadlinqs corpus references CVE-2026-67278, either in the campaign’s CVE list or as an indicator on the campaign record.

Sources

Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.

Vendor advisory and patch

Exploit and proof of concept

Technical analysis

Third-party advisory

Full detection coverage & IOCs for threats exploiting CVE-2026-67278 are available via the Threadlinqs MCP server (Purple tier). View plans →

← all vulnerabilities · Markdown version · Threadlinqs Intelligence