XSS in Statcounter – Free Real Time Visitor Stats

CVE-2026-6275

The StatCounter – Free Real Time Visitor Stats plugin for WordPress is vulnerable to Stored Cross-Site Scripting in versions up to, and including, 2.1.1 This is due to insufficient output escaping on the post author's nickname in the statcounter_addToTags() function. The function is hooked to wp_head and fires on every single post page. It retrieves the post author's nickname via the_author_meta() and echoes it directly into a JavaScript double-quoted string context inside a <script> block without applying esc_js() or any equivalent JavaScript-context escaping. This makes it possible for authenticated attackers with Author-level access and above to inject arbitrary web scripts into pages that will execute whenever any user (including unauthenticated visitors) accesses a post authored by the attacker.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (26.1th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 26th percentile — 26.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-6275: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-6275?
CVE-2026-6275 is a medium-severity vulnerability in Statcounter – Free Real Time Visitor Stats, classified under Cross-site Scripting. CVSS score: 6.4/10. Published 2026-05-29.
How severe is CVE-2026-6275?
Medium severity. CVSS v3 base score is 6.4 out of 10.