by Kastro
Paper/Archive/CVE-2026-121491

CVE-2026-121491

Unknown Fiber Admin — Fiber Admin 3.1.0 - 4.0.0 - Unauthenticated RCE via Host Header

EPSS 0.2%CVSS 9.0
critical.is priorityof 100
30
CVSS 9.0 (ADP)9.0 / 10 × 3027.0Not in CISA KEV+300.0EPSS percentile 13.1.131 × 202.6No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
Fiber Admin3.1.0 – < 4.0.14.0.1CNA

Scores by source

CISA ADP9.0CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: total

References

exploitwpscan.com/vulnerability/42b9773d-9c69-4435-be20-ae86f52b4608