Vulnerability · Published Oct 27, 2026 · Assigned by WatchGuard
CVE-2026-93857Fireware OS Pre-Authentication Stack Buffer Overflow in SIP Proxy Allows Remote Code Execution
Critical 9.2
In plain English
A critical-severity buffer overflow in Fireware OS from WatchGuard. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 47% of all known vulnerabilities).
Severity (CVSS 4.0)9.2Critical
Exploit odds (30 days)0.6%top 53.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
A stack-based buffer overflow vulnerability in Fireware OS's SIP proxy allows a remote, unauthenticated attacker to execute arbitrary code by sending a specially crafted request through a policy that uses the SIP proxy.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| WatchGuard | Fireware OS | 2025.1 – before 2026.412.0 – before 12.12.4 |
| WatchGuard | Fireware OS | 12.0 – before 12.5.22 |
Weakness: CWE-120, CWE-121, CWE-787 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
References
- https://psirt.watchguard.com/CVE-2026-93857 vendor-advisory