AEGLIX vulnerability intelligence
CVE-2026-67277
HIGH · CVSS 8.8 · Analyzed
Published: 2026-09-05 · Updated: 2026-09-11 · Source: NVD
Vulnerability overview
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)
Severity and scoring
- CVSS score
- 8.8 · HIGH
- CVSS version
- 4.0
- CVSS vector
- 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- Weaknesses
- CWE-306
CVSS measures technical severity; it does not establish whether this vulnerability is being exploited in your environment.
Known exploitation and remediation
Listed in CISA’s Known Exploited Vulnerabilities catalog.
- Affected product
- MikroTik · RouterOS
- Added to catalog
- 2026-09-10
- 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.
- CISA remediation due date
- 2026-09-13
CISA deadlines apply to the organizations covered by its directives. Confirm your own remediation requirements.
Verify affected versions and patch availability in the vendor advisory before making changes.
Affected products and versions
cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*
From (inclusive): 6.0
Before (exclusive): 6.49.21
cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*
From (inclusive): 7.0
Before (exclusive): 7.23.4
cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*
From (inclusive): 7.24
Before (exclusive): 7.24.2
These are NVD CPE applicability entries. Some products depend on configuration conditions; consult the official record to confirm applicability.
Advisories and references
- 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