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Exploited High 8.2

Vulnerability in Mikrotik Routeros

CVE-2026-67277 First seen on SecPulse

AI summary

Produced by SecPulse using an external AI model; it may contain mistakes. Check the original description and references below before acting on it.

A vulnerability tracked as CVE-2026-67277 has been found in Mikrotik Routeros.
Risk of unauthorized operations or information disclosure. CVSS score: 8.2/10.
Note: CISA has officially confirmed this is actively exploited in the wild. Treat it with elevated urgency.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Mikrotik Routeros CVE-2026-67277" on the vendor's site.

CVE-2026-67277 (Mikrotik Routeros) — CWE-306 / CVSS v3 8.2
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Listed in CISA KEV — actively exploited, treat as top priority.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

What is the problem

A vulnerability (CWE-306) exists in Mikrotik Routeros.

Affected scope

Check the vendor advisory for the affected versions of Mikrotik Routeros.

Severity

Severity: High (CVSS 8.2/10). Risk of unauthorized operations or information disclosure. Listed in CISA KEV — actively exploited in the wild, treat as top priority.

How to fix

Update to the patched release per vendor advisory.

Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Routeros' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposureidentify
    grep -r 'Routeros' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で Routeros を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Consider incident declarationescalate
    Notify SOC / on-call

    CISA KEV登録済 = 実環境で悪用が観測されている。侵入の兆候があればインシデント対応宣言、無くてもパッチ適用までWAF強化を最優先で。

  3. 3
    Post-deployment verificationverify
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Original description The description as published by the source.

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)

Source: NIST National Vulnerability Database NVD GitHub Advisory CISA KEV

References

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