Reference page — cumulative record through Sunday, October 4, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-67277

CVE-2026-67277HIGH

Mikrotik RouterOS — Kernel memory disclosure and denial of service in MikroTik RouterOS btest service

  AV  AC  AT  PR  UI  VC  VI  VA   CVSS    EPSS   %ile   KEV
   N   L   N   N   N   L   N   H    8.8   .0156   74.4   YES

AFFECTED
  Product   Versions  Fixed
  RouterOS  7.24 –    —

TIMELINE
  Jul 29  Reserved by CERT-PL
  Sep 5   Published (CNA: CERT-PL)
  Sep 8   EXPLOIT PUBLISHED — CVE-2026-67277 (Mikrotik RouterOS). Public exploit reference added.
  Sep 10  EXPLOIT PUBLISHED — CVE-2026-67277 (Mikrotik RouterOS). Public exploit reference added.
  Sep 10  ADDED TO KEV — CVE-2026-67277 (Mikrotik RouterOS). Remediation due September 13, 2026.
  Sep 14  DUE DATE PASSED — CVE-2026-67277 (Mikrotik RouterOS). CISA remediation deadline was September 13, 2026; still in catalog.

CWE-306 · CNA: CERT-PL · CVSS v4.0 · 8 references · NVD status: Analyzed · KEV due September 13, 2026

Description

RouterOS accepts a "related" btest connection before the corresponding primary session has completed authentication. An unauthenticated client can use this state to start an IPv4 UDP test. With "random-data=false", the sender transmits an uninitialized tail from a kernel packet buffer. A separate unchecked, inverted packet-size interval causes unsigned integer underflow, anomalously large fragmented output, and can restart the RouterOS kernel. This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)

Lifecycle

Complete event history — 6 events, chronological
Date	Event	Detail
July 29, 2026	Reserved	Reserved by CERT-PL
September 5, 2026	Published	Published (CNA: CERT-PL)
September 8, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-67277 (Mikrotik RouterOS). Public exploit reference added.
September 10, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-67277 (Mikrotik RouterOS). Public exploit reference added.
September 10, 2026	KEV ADDED	ADDED TO KEV — CVE-2026-67277 (Mikrotik RouterOS). Remediation due September 13, 2026.
September 14, 2026	DUE DATE PASSED	DUE DATE PASSED — CVE-2026-67277 (Mikrotik RouterOS). CISA remediation deadline was September 13, 2026; still in catalog.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
Mikrotik	RouterOS	—	7.24	—

Weaknesses

CWE-306

References (8)

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/6-49-21-long-term-is-released/272802 [Release Notes]
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]
https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/ [Exploit, Third Party Advisory]
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-67277 [US Government Resource]

Authoritative record: CVE-2026-67277 at cve.org

Vendors: mikrotik

Weaknesses: CWE-306

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-67277 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Sunday, October 4, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.