CVE-2026-55490

Published: Jul 7, 2026Modified: Jul 10, 2026

6.5

Vector

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

Exploitability: 2.8 / Impact: 3.6

Source: security-advisories@github.com (Secondary)

Description

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.

Affected (1)

Products: Openwrt: Openwrt

1 product

Configuration A

1 vulnerable

Vulnerable Software	Affected Versions
Openwrt Openwrt	Before 25.12.5

Related CWEs

Integer Underflow (Wrap or Wraparound)

The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.

References (3)

https://github.com/openwrt/openwrt/commit/63c0767f3d02f7b10b0f0b5293366bd059a08ca5

Source: security-advisories@github.com

Patch

https://github.com/openwrt/openwrt/releases/tag/v25.12.5

Source: security-advisories@github.com

Release Notes

https://github.com/openwrt/openwrt/security/advisories/GHSA-9558-77jp-g3fw

Source: security-advisories@github.com

ExploitVendor Advisory

Timeline

No history available yet.