CVE-2026-55490

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

Published Jul 7, 2026 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Openwrt
Openwrt openwrt
Vendors & Products Openwrt
Openwrt openwrt
Type Values Removed Values Added
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.
Title OpenWrt: EAD Integer Underflow → Pre-Auth Denial of Service
Weaknesses CWE-191
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Jul 8, 2026, 1:52 PM
Reserved
Jun 16, 2026, 10:28 PM
Status
Analyzed
Published
Jul 7, 2026, 10:16 PM
Modified
Jul 10, 2026, 5:37 PM