What is the CVSS score of CVE-2026-20408?

CVE-2026-20408 has a CVSS 3.1 base score of 8.8 (High). CVSS vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.0%.

Which versions of Openwrt are affected by CVE-2026-20408?

A critical wireless LAN vulnerability (CVE-2026-20408) allows attackers with network proximity to execute privilege escalation attacks, potentially compromising connected devices and sensitive data.

How to fix or mitigate CVE-2026-20408?

Within 24 hours: Identify all affected WLAN equipment in inventory and isolate critical networks from compromised access points; notify all users of temporary access restrictions. Within 7 days: Implement network segmentation to restrict lateral movement, enable enhanced wireless monitoring/logging, and contact vendor for patch timeline or alternative solutions. Within 30 days: Deploy compensating controls (see below), conduct network security assessment, and establish contingency plan for equipment replacement if patch remains unavailable.

Openwrt CVE-2026-20408

HIGH

Heap-based Buffer Overflow (CWE-122)

2026-02-02 security@mediatek.com

Buffer Overflow Privilege Escalation Openwrt Software Development Kit

8.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

8.8 HIGH

AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Adjacent

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 22:01 vuln.today

CVE Published

Feb 02, 2026 - 09:15 nvd

HIGH 8.8

DescriptionCVE.org

In wlan, there is a possible out of bounds write due to a heap buffer overflow. This could lead to remote (proximal/adjacent) escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: WCNCR00461651; Issue ID: MSV-4758.

AnalysisAI

OpenWRT and related SDKs are vulnerable to a heap buffer overflow in the WLAN component that allows adjacent network attackers to execute privilege escalation without user interaction or special permissions. The out-of-bounds write condition enables attackers on the same network segment to gain elevated system privileges. No patch is currently available for this vulnerability.

Technical ContextAI

Classified as CWE-122 (Heap-based Buffer Overflow). Affects Software Development Kit. In wlan, there is a possible out of bounds write due to a heap buffer overflow. This could lead to remote (proximal/adjacent) escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: WCNCR00461651; Issue ID: MSV-4758.