Critical severity · published Oct 27, 2026
CVE-2026-93857
Fireware OS Pre-Authentication Stack Buffer Overflow in SIP Proxy Allows Remote Code Execution
New
9.2
CVSS
–
EPSS
No
On KEV
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.
Exploitation
Is it being used?
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FO
Fireware OS · WatchGuard
2025.1 before 2026.4; 12.0 before 12.12.4; 12.0 before 12.5.22 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-93857
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-93857
psirt.watchguard.com
https://psirt.watchguard.com/CVE-2026-93857
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