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OpenAdvisories
Medium · 6.5 CVE-2026-55490 EUVD-2026-42110

OpenWrt: EAD Integer Underflow → Pre-Auth Denial of Service

Published Jul 7, 2026 · Updated Jul 8, 2026 · Assigned by GitHub_M

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 products

VendorProductAffectedFixed
openwrt openwrt < 25.12.5 —

References