CVE Tools
Sign in

CVE-2026-55490

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

Published: Jul 7, 2026Updated: Jul 10, 2026 Sources: CVE List NVDCWE-191
6.5MEDIUM
NVD MITRE
EPSS Score
1.0%
Top 40.9%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:AAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:AAttack Vector
Adjacent
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
Open in CVSS calculator →

Weaknesses

CWE-191

Affected Products

openwrt
oss-project·DEaka lede
openwrtEmbeddedOS
Operating Systems / linux-distro

Exploitability

Official Patch Available
Is your org exposed to CVE-2026-55490?We can run the check for you — a free external exposure review, no install. Check my exposure

Attack Graph

Products CVE Techniques Tactics

Click technique nodes for MITRE ATT&CK details · drag to pan · Ctrl/⌘ + scroll to zoom, or go fullscreen.

MITRE ATT&CK

1 technique
Initial Access
View detailed technique mapping

References

https://github.com/openwrt/openwrt/commit/63c0767f3d02f7b10b0f0b5293366bd059a08ca5
github.com
https://github.com/openwrt/openwrt/releases/tag/v25.12.5
github.com
https://github.com/openwrt/openwrt/security/advisories/GHSA-9558-77jp-g3fw
github.com

Unlock Complete Vulnerability Intelligence

Get the full picture for CVE-2026-55490 and every CVE in our database. Create a free account — no credit card required.

Create Free Account
Plain-language analysis
Impact assessment and exploitation scenario in plain English
Attack graph visualization
Interactive attack path and kill chain mapping
Exploit details & PoC links
ExploitDB, Metasploit, GitHub PoCs with direct links
Nuclei scanner templates
Ready-to-use vulnerability scanner templates
Full remediation guide
Patch instructions, workarounds, and compliance impact
Interactive AI chat
Ask questions about this vulnerability in natural language
Related vulnerabilities
Semantically similar CVEs and attack patterns
REST API & MCP access
Integrate vulnerability data into your workflows