CVE-2021-4356

CRITICALNVD 9.09.0—
EchelonGraph scoreMEDIUM confidence

Score 9.0 from GitHub Security Advisory (severity: CRITICAL) published 2023-06-07. NVD baseline CVSS 9.0; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.0
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 2%CVSS: 9.0Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

The Frontend File Manager plugin for WordPress is vulnerable to Unauthenticated Arbitrary File Download in versions up to, and including, 18.2. This is due to lacking authentication protections, capability checks, and sanitization, all on the wpfm_file_meta_update AJAX action. This makes it possible for unauthenticated attackers to download arbitrary files on the site, potentially leading to site takeover.

CVSS v3
9.0
EG Score
9.0(medium)
EG Risk
41(Track)
EG Risk 41/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity90% × 45%
Exploitation2% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
72.0%
KEV
Not listed

Published

June 7, 2023

Last Modified

April 8, 2026

References (6)

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 13× in last 7d / 45× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 136 total refreshes for this CVE.

  1. 2026-07-24 14:15 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2021-4356?
CVE-2021-4356 is a critical vulnerability published on June 7, 2023. The Frontend File Manager plugin for WordPress is vulnerable to Unauthenticated Arbitrary File Download in versions up to, and including, 18.2. This is due to lacking authentication protections, capability checks, and sanitization, all on the wpfmfilemeta_update AJAX action. This makes it possible…
When was CVE-2021-4356 disclosed?
CVE-2021-4356 was first published in the National Vulnerability Database on June 7, 2023, with the most recent update on April 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-4356 actively exploited?
CVE-2021-4356 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 72.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-4356?
CVE-2021-4356 has a CVSS v3 base score of 9.0 (NVD).
How do I remediate CVE-2021-4356?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-4356, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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