CVE-2026-55490

OpenWrt is a Linux operating system targeting embedded devices. Before v25.12.5, an integer underflow in handle_send_a() of the Emergency Access Daemon allows any unauthenticated attacker on the local network to crash the daemon by sending a single crafted UDP packet. The message length underflows before a bounds check and is then passed to memcpy as a very large size. This issue is fixed v25.12.5.

CVSS v3 6.5 MEDIUM

6.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.8 / Impact : 3.6

Attack Vector ADJACENT_NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/openwrt/openwrt/commit/63c0767f3d02f7b10b0f0b5293366bd059a08ca5	Patch
https://github.com/openwrt/openwrt/releases/tag/v25.12.5	Release Notes
https://github.com/openwrt/openwrt/security/advisories/GHSA-9558-77jp-g3fw	Exploit Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:o:openwrt:openwrt:*:*:*:*:*:*:*:*

History

10 Jul 2026, 17:37

Type	Values Removed	Values Added
References	~~() https://github.com/openwrt/openwrt/commit/63c0767f3d02f7b10b0f0b5293366bd059a08ca5 -~~	() https://github.com/openwrt/openwrt/commit/63c0767f3d02f7b10b0f0b5293366bd059a08ca5 - Patch
References	~~() https://github.com/openwrt/openwrt/releases/tag/v25.12.5 -~~	() https://github.com/openwrt/openwrt/releases/tag/v25.12.5 - Release Notes
References	~~() https://github.com/openwrt/openwrt/security/advisories/GHSA-9558-77jp-g3fw -~~	() https://github.com/openwrt/openwrt/security/advisories/GHSA-9558-77jp-g3fw - Exploit, Vendor Advisory
First Time		Openwrt Openwrt openwrt
CPE		cpe:2.3:o:openwrt:openwrt::::::::

07 Jul 2026, 22:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-07-07 22:16

Updated : 2026-07-10 17:37

NVD link : CVE-2026-55490

Mitre link : CVE-2026-55490

CVE.ORG link : CVE-2026-55490

JSON object : View

Products Affected

openwrt

openwrt

CWE

CWE-191

Integer Underflow (Wrap or Wraparound)

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