CVE-2026-55490 Details
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.
A denial-of-service vulnerability has been identified in the Emergency Access Daemon (EAD) of OpenWrt, a Linux operating system for embedded devices. This issue, present in versions prior to 25.12.5, allows any unauthenticated attacker on the local network to crash the daemon by sending a single crafted UDP packet. The vulnerability arises from an integer underflow in the 'handle_send_a()' function, where the message length is improperly validated before being used in a memory copy operation. As a result, the daemon can be forced to read and write beyond its allocated memory, causing a crash.
Users are advised to upgrade to OpenWrt version 25.12.5 or later, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jul 8, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-191 | Integer Underflow (Wrap or Wraparound) | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| openwrt openwrt | < 25.12.5 |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 10, 2026 | Initial Analysis | [email protected] |
| Jul 8, 2026 | CVE Modified | CISA-ADP |
| Jul 7, 2026 | New CVE Received | [email protected] |