CVE-2026-4266

8.4 highEPSS 0.3%

High (8.4) in watchguard fireware. EPSS 0.3% chance of exploitation in the next 30 days.

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.

Severity

CVSS 4.0

8.4 high

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

CVSS 3.1

6.7 medium

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.3% chance of exploitation in the next 30 days; higher than 19% of CVEs (scores of 2026-10-31)
CWE: CWE-502
Published: 2026-03-30
Modified: 2026-08-28
Record from: the NVD, synced 2026-10-19

Affected

watchguard:fireware

References

https://psirt.watchguard.com/CVE-2026-4266
https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2026-00007

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