Is there a public exploit for CVE-2026-121491?

No public exploit for CVE-2026-121491 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-121491?

CVE-2026-121491 scores CVSS 9 (v3.1), rated critical. EPSS puts the chance of exploitation in the next 30 days at 0.22%.

What does CVE-2026-121491 affect?

CVE-2026-121491 affects Unknown Fiber Admin.

9.0 Critical

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…

CVE-2026-121491

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.

Assessment

CVSS: 9 (v3.1)
Severity: Critical
EPSS: 0.22% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 7 November 2026
Last updated: 7 November 2026
Affected: Unknown · Fiber Admin
Assigner: WPScan

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

At the source

EUVD (ENISA)

References

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

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