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
0.5%
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?
Exploit prediction (EPSS)0.5% · higher than 41% of CVEs
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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