What is CVE-2026-19855?

CVE-2026-19855 is a medium-severity vulnerability in Cleantalk, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 6.5/10. Published 2026-09-09.

How severe is CVE-2026-19855?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Cleantalk

CVE-2026-19855

The CleanTalk WordPress plugin before 6.87 does not prevent unauthenticated, user-supplied comment content from being passed to WordPress's shortcode engine, allowing any visitor to have arbitrary shortcodes registered on the site executed server-side and rendered to every subsequent visitor of the page.

Published 2026-09-09 · last modified 2026-09-09.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.002 (7.5th percentile), scored 2026-10-24.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 7th percentile — 7.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000

Affected products

Cleantalk

Weakness classification (CWE)

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

References

wpscan.com/vulnerability/c27f3657-261a-46cd-860c-0bdf5c849190/ (technical-description, exploit, vdb-entry)

Frequently asked questions

What is CVE-2026-19855?: CVE-2026-19855 is a medium-severity vulnerability in Cleantalk, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 6.5/10. Published 2026-09-09.
How severe is CVE-2026-19855?: Medium severity. CVSS v3 base score is 6.5 out of 10.