What is CVE-2026-10513?

CVE-2026-10513 is a high-severity vulnerability in Pfefferle Webmention, classified under Cross-site Scripting. CVSS score: 7.2/10. Published 2026-06-30.

How severe is CVE-2026-10513?

High severity. CVSS v3 base score is 7.2 out of 10.

XSS in Pfefferle Webmention

CVE-2026-10513

The Webmention plugin for WordPress is vulnerable to Stored Cross-Site Scripting in versions up to and including 5.8.0 via parser-derived 'avatar' and 'url' author metadata. This is due to insufficient input sanitization and output escaping on user-supplied MF2 author properties processed by the unauthenticated webmention REST endpoint and rendered directly into HTML 'value' attributes by the edit-comment-form template without esc_attr() or esc_url(). This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a privileged user (moderator or administrator) opens the affected comment edit screen.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.002 (14.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N.

Affected products

Pfefferle Webmention — versions 0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

Frequently asked questions

What is CVE-2026-10513?: CVE-2026-10513 is a high-severity vulnerability in Pfefferle Webmention, classified under Cross-site Scripting. CVSS score: 7.2/10. Published 2026-06-30.
How severe is CVE-2026-10513?: High severity. CVSS v3 base score is 7.2 out of 10.