Which products and versions are affected by CVE-2026-67277?

Affected: RouterOS (Mikrotik) versions >= 7.0.0, >= 7.24. The full list is in the CVE brief.

Is CVE-2026-67277 being exploited in the wild?

It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Sep 5, 2026.

Is CVE-2026-67277 in the CISA KEV catalog?

Yes. It was added on Sep 10, 2026 with a federal remediation due date of Sep 13, 2026.

Is there a public exploit for CVE-2026-67277?

Public exploit code is available.

Is there a fix for CVE-2026-67277?

Fixed versions are available, including RouterOS 6.49.21, RouterOS 7.23.4, RouterOS 7.24.2.

How urgently should CVE-2026-67277 be patched?

Brandefense priority: patch immediately, because it is listed as exploited in the wild.

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Vulnerability Intelligence

CVE-2026-67277

HighExploitedPublic exploit

RouterOS accepts a "related" btest connection before the corresponding primary session has completed authentication.

Published Sep 5, 2026 · Updated Sep 11, 2026 · Also known as EUVD-2026-72025, GHSA-6q2x-6fhj-r3w8

Key Facts

Patch immediately

CVE-2026-67277 is a high-severity vulnerability (CVSS 8.8 v4) affecting RouterOS (Mikrotik).
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Sep 5, 2026. Public exploit code is available.
EPSS estimates a 1.6% probability of exploitation in the next 30 days.
Fixed versions are available, including RouterOS 6.49.21, RouterOS 7.23.4, RouterOS 7.24.2.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.

CVSS v4

8.8

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N

EPSS (30-day exploit likelihood)

1.6%

Higher than 74.8% of all scored CVEs

Exploited in the wild

Yes

4 catalog listings

Public exploit code

Available

Proof-of-concept or weaponized module

Get the full CVE-2026-67277 brief as a PDF

Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.

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)

Known-Exploited Catalog Listings

Catalog	Added	Remediation due	Ransomware use
CISA KEV	Sep 10, 2026	Sep 13, 2026	Not reported
Industry KEV feed	Sep 5, 2026	Sep 13, 2026	Not reported
CIRCL KEV	Sep 5, 2026	Sep 13, 2026	Not reported
ENISA EUVD	Sep 5, 2026	n/a	Not reported

Required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Affected Products

4 affected entries in total

Product	Affected versions	Fixed in
RouterOSMikrotik	>= 7.0.0, >= 7.24	7.25.1

Patched Releases

RouterOS

6.49.21, 7.23.4, 7.24.2, 7.25.1

Timeline

Publicly disclosed
Sep 5, 2026
Added to Industry KEV feed
Sep 5, 2026
Added to CIRCL KEV
Sep 5, 2026
Added to ENISA EUVD
Sep 5, 2026
Added to CISA KEV
Sep 10, 2026
Last updated
Sep 11, 2026

Weakness Type

CWE-306 Missing Authentication for Critical Function

References

5 more references in the full CVE brief

FAQ

Common Questions.

RouterOS accepts a "related" btest connection before the corresponding primary session has completed authentication.
Affected: RouterOS (Mikrotik) versions >= 7.0.0, >= 7.24. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Sep 5, 2026.
Yes. It was added on Sep 10, 2026 with a federal remediation due date of Sep 13, 2026.
Public exploit code is available.
Fixed versions are available, including RouterOS 6.49.21, RouterOS 7.23.4, RouterOS 7.24.2.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.

Is CVE-2026-67277 Running On Your Attack Surface?

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