CVE-2026-55490CWE-191

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

Medium · published July 7, 2026

CVSS v3.1
6.5
EPSS
1%
Percentile
51.9
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
6.5 · MEDIUM
Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00682 · 51.9th percentile
Weakness
CWE-191 · Integer Underflow (Wrap or Wraparound)
Published
2026-07-07T21:08Z
EPSS history
Timeline
  • 07 JUL 21:08Z
    OpenWrt: EAD Integer Underflow → Pre-Auth Denial of Service
    cvelistv5