CVE-2026-121491

Fiber Admin 3.1.0 - 4.0.0 - Unauthenticated RCE via Host Header

Published Nov 7, 2026 CVSS 3.1 · 9.0 Critical EPSS < 1% KEV · Not listed
Description
The Fiber Admin WordPress plugin before 4.0.1 does not validate or escape a request header before writing it into a PHP file it regenerates on an unprotected admin hook, allowing unauthenticated attackers to execute arbitrary code when its custom database error page is enabled and they win a race against an administrator saving its settings.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Wordpress-extensions
Wordpress-extensions fiber Admin
Vendors & Products Wordpress-extensions
Wordpress-extensions fiber Admin
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Weaknesses CWE-20
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 9.0, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H'}

Type Values Removed Values Added
Weaknesses CWE-20
CWE-94
Type Values Removed Values Added
Description The Fiber Admin WordPress plugin before 4.0.1 does not validate or escape a request header before writing it into a PHP file it regenerates on an unprotected admin hook, allowing unauthenticated attackers to execute arbitrary code when its custom database error page is enabled and they win a race against an administrator saving its settings.
Title Fiber Admin 3.1.0 - 4.0.0 - Unauthenticated RCE via Host Header
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
WPScan
Published
Updated
Nov 7, 2026, 6:16 PM
Reserved
Nov 3, 2026, 2:07 PM
Status
Deferred
Published
Nov 7, 2026, 6:16 AM
Modified
Nov 10, 2026, 4:28 PM