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CVE-2026-4357

CRITICAL 10 PoC AVAILABLE

Published 2026-09-02 · Last modified 2026-09-02

The Embed HTML5 Game WordPress plugin through 1.3 does not properly restrict who can upload files via the plugin, as well as what can be uploaded, making it possible for unauthenticated attackers to upload PHP backdoors on affected sites.

EXPLOIT AVAILABLE

Public exploit or PoC code exists. Modeled probability is still low, but the barrier to attack is reduced — watch closely.

Exploitation likelihood

0.3%chance of exploitation in 30 days · 23rd percentile

○ In CISA KEV ● Public exploit / PoC

Impact if exploited

10CVSS 3.1 · CRITICAL

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-4357/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-4357/poc.json

Affected

Vendors Unknown

Products Embed Html5 Game

Weakness (CWE)

  • CWE-434: Unrestricted Upload of File with Dangerous Type

CVSS vector

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

All CVSS metrics

  • CRITICAL 10 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
  • CRITICAL 10 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

References

Exploits & PoC

Sources: NVD · CVE.org · EPSS