What is CVE-2026-86833?

CVE-2026-86833 is a medium-severity vulnerability in Metform, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 5.4/10. Published 2026-10-07.

How severe is CVE-2026-86833?

Medium severity. CVSS v3 base score is 5.4 out of 10.

Vulnerability in Metform

CVE-2026-86833

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.

Published 2026-10-07 · last modified 2026-10-07.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Metform

Weakness classification (CWE)

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

References

wpscan.com/vulnerability/6d6850d6-6fdf-4b97-9ccb-c90f9ed01ab0/ (technical-description, exploit, vdb-entry)

Frequently asked questions

What is CVE-2026-86833?: CVE-2026-86833 is a medium-severity vulnerability in Metform, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 5.4/10. Published 2026-10-07.
How severe is CVE-2026-86833?: Medium severity. CVSS v3 base score is 5.4 out of 10.