CVE-2026-4266: high-severity vulnerability in WatchGuard Fireware OS
WatchGuard Firebox Insecure Deserialization in Fireware Access Portal
Published · Updated
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.4epss 0.3%
An Insecure Deserialization vulnerability in WatchGuard Fireware OS allows an attacker that has obtained write access to the local filesystem through another vulnerability to execute arbitrary code in the context of the portald user.
Note, this vulnerability does not affect Firebox platforms that do not support the Access Portal feature, including the T15 and T35.
CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Affected products
WatchGuard · Fireware OSRelated CVEs — WatchGuard Fireware OS
In the same product, most dangerous first.
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