Vulnerability details

CVE-2026-121491

Fiber Admin

Fiber Admin 3.1.0 - 4.0.0 - Unauthenticated RCE via Host Header

CVSS 3.1

9.0Critical

Official 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.

CVSS scores

Score	Version	Source	Vector
9.0Critical	3.1	CISA ADP / Vulnrichment (CISA-ADP)	`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H`

Affected products

Vendor	Product	Versions	Source
—	Fiber Admin	3.1.0 ≤ v < 4.0.1	CVEProject cvelistV5 (CNA)

References and advisories

https://wpscan.com/vulnerability/42b9773d-9c69-4435-be20-ae86f52b4608/ exploitvdb-entrytechnical-description

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Details

Published: 2026-11-07
Last updated: 2026-11-07
State: Published
Assigner (CNA): WPScan
Kolun priority: 32 · Low

Exploit prediction (EPSS)

0.39%

Probability of exploitation in 30 days

33.9%

Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable: No
Exploitation: None
Technical impact: Total

Weaknesses (CWE)

CWE-94
Improper Control of Generation of Code ('Code Injection')