All vulnerabilities
CVE-2026-86133

Fireware OS Pre-Authentication Integer Underflow in iked Allows Remote Denial of Service

WatchGuard Fireware OSNetwork & edge
Open in ThreatlineRecord JSON
CVSS
8.2High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.35%Chance of exploitation activity in the next 30 days, higher than 26% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in2026.3.2Also 2026.2.3, 12.12.3 and 1 moreCVE List
Published29 Sep 2026Updated 30 Sep 2026CVE List

What fixes it

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

An integer underflow vulnerability in the WatchGuard Fireware OS IKE daemon (iked) allows a remote attacker who has completed the initial IKEv2 handshake to crash the iked process by sending a specially crafted encrypted IKEv2 message, resulting in a denial of service.

Text from CVE List

Affected versions 4

  • Fireware OSaffected: 2026.3 before 2026.3.2CVE List
  • Fireware OSaffected: 2025.0 before 2026.2.3CVE List
  • Fireware OSaffected: 12.0 before 12.12.3CVE List
  • Fireware OSaffected: 12.0 before 12.5.21CVE List

References 1