Overview
CVE-2026-67277 has been added to the CISA Known Exploited Vulnerabilities catalog. Published on September 05, 2026. Threat actors are actively exploiting this vulnerability in real-world attacks.
RouterOS accepts a "related" btest connection before the corresponding primary session has completed authentication.
Threat Intelligence
| Metric | Value |
|---|---|
| CVE ID | CVE-2026-67277 |
| Severity | HIGH |
| CVSS Score | 0.0/10 |
| CISA KEV | ✅ Yes — Actively Exploited |
| KEV Date Added | September 10, 2026 |
| Remediation Deadline | September 13, 2026 |
| EPSS Score | 0.4% exploit probability |
| EPSS Percentile | Top 100% of all CVEs |
Why This Matters
This vulnerability has been added to the CISA Known Exploited Vulnerabilities (KEV) catalog, which means threat actors are actively exploiting it in real-world attacks.
Federal agencies are required to remediate by September 13, 2026. All organizations should treat this deadline as a strong recommendation.
CISA Notes: https://mikrotik.com/supportsec/september-2026-vulnerability/ ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-67277
Recommended Actions
- Verify exposure — Determine if your environment uses the affected software.
- Apply patches — Update to the latest version as soon as a fix is available.
- Monitor for compromise — Check logs for unusual activity.
- Meet the deadline — CISA recommends remediation by September 13, 2026.
References
CVE data aggregated from the National Vulnerability Database (NVD), CISA Known Exploited Vulnerabilities catalog, and FIRST EPSS. Analysis updated as new intelligence becomes available. Last updated: 2026-09-10.