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TI-2026-40045 Aliases CVE-2026-55490

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

Priority MEDIUM 62CWE-191Published · Updated

Key facts

Attack vector
Adjacent network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-191 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00682 52nd percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed openwrt (openwrt): 25.12.5

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
openwrtopenwrtbefore 25.12.525.12.5Patch availableCNA
  • openwrt Vendoropenwrt Affected before 25.12.5 Fixed in 25.12.5 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:o:openwrt:openwrt:*:*:*:*:*:*:*:*before 25.12.5Vulnerableopenwrt
  • cpe:2.3:o:openwrt:openwrt:*:*:*:*:*:*:*:* Versions before 25.12.5 Vulnerable ·openwrt

Remediation

  • Fix · CNA openwrt (openwrt) Fixed in 25.12.5

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-55490

References

Exploit 1

Patch 1

Other 1

  • TI-2024-13053 Improper input validation in MediaTek MT6890, MT7915, MT7916, MT7981, MT7986 CVSS 3.1CRITICAL 9.8
  • TI-2026-44983 Cross-site scripting in openwrt CVSS 3.1CRITICAL 9.6
  • TI-2023-09914 LuCI openwrt-22.03 branch git-22.361.69894-438c598 was discovered to contain a stored… CVSS 3.1MEDIUM 5.4
  • TI-2026-44982 OpenWrt: ACL bypass and arbitrary root file read via cgi-io cgi-download CVSS 3.1MEDIUM 4.9
  • TI-2026-23701 OpenWrt Project has a Stack-based Buffer Overflow vulnerability via IPv6 reverse DNS lookup CVSS 4.0CRITICAL 9.5
  • TI-2026-23700 OpenWrt Project has Stack-based Buffer Overflow in DNS PTR Query CVSS 4.0CRITICAL 9.5
See all 136 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences