Medium severity · published Jul 2, 2026
CVE-2026-13371
WatchGuard Firebox Management Web UI Denial of Service via Unsafe Deserialization
4.9
CVSS
0.6%
EPSS
No
On KEV
Description
An authenticated administrator can trigger a denial-of-service condition in the Fireware Management Web UI by sending malformed or crafted data to the put_data endpoint, which performs unsafe deserialization of the attacker-supplied input.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
High
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 48% 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 2026.2.1; 12.0 before 12.12.1; 12.0 before 12.11.9; 12.0 before 12.5.19 · source: vendor
FI
Fireware · Watchguard
2025.1 before 2026.2.1; 12.5 before 12.5.19; 12.0 before 12.12.1 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-13371
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-13371
Broken Link
https://psirt.watchguard.com/CVE-2026-13371
Vendor Advisory
https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2026-00014
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