All vulnerabilities
CVE-2026-103593

Fireware OS Stack Buffer Overflow in Logging Service Allows Remote Code Execution

WatchGuard Fireware OSNetwork & edge
Open in ThreatlineRecord JSON
CVSS
9.1Critical
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)No scoreNo FIRST EPSS score in this snapshot yet
Fixed in2026.4Also 12.12.4, 12.5.22CVE List
Published27 Oct 2026Updated 27 Oct 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

A stack-based buffer overflow vulnerability in the Fireware OS logging service allows a network-adjacent attacker who can impersonate or intercept traffic to the configured log server to execute arbitrary code with root privileges by presenting a specially crafted certificate.

Text from CVE List

Affected versions 3

  • Fireware OSaffected: 2025.1 before 2026.4CVE List
  • Fireware OSaffected: 12.0 before 12.12.4CVE List
  • Fireware OSaffected: 12.0 before 12.5.22CVE List

References 1