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CVE-2026-86833

MEDIUM 5.4 PoC AVAILABLE

Published 2026-10-07 · Last modified 2026-10-07

The MetForm WordPress plugin before 4.3.1 does not sanitize or escape submitted form-field values before inserting them into the HTML body of its email notifications, allowing unauthenticated attackers to inject arbitrary markup into the administrator and submitter notification emails the site sends.

EXPLOIT AVAILABLE

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

Exploitation likelihood

0.2%chance of exploitation in 30 days · 5th percentile

○ In CISA KEV ● Public exploit / PoC

Impact if exploited

5.4CVSS 3.1 · MEDIUM

  • ConfidentialityLow
  • IntegrityLow
  • AvailabilityNone

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ⚠User interaction: A user must take an action (click / open a file)
  • ✓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-2026-86833/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-2026-86833/poc.json

Affected

Vendors Unknown

Products Metform

Weakness (CWE)

  • CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

CVSS vector

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

All CVSS metrics

  • MEDIUM 5.4 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
  • MEDIUM 5.4 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

References

Exploits & PoC

Sources: NVD · CVE.org · EPSS