XSS in Specialk Simple Download Counter

CVE-2026-4278

The Simple Download Counter plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'sdc_menu' shortcode in all versions up to, and including, 2.3. This is due to insufficient input sanitization and output escaping on user-supplied shortcode attributes, specifically the 'text' and 'cat' attributes. The 'text' attribute is output directly into HTML content on line 159 without any escaping (e.g., esc_html()). The 'cat' attribute is used unescaped in HTML class attributes on lines 135 and 157 without esc_attr(). This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

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: 0.004 (33.7th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 34th percentile — 33.7% 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-2026-4278: held from 0.002 to 0.004.

EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.002

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-4278?
CVE-2026-4278 is a medium-severity vulnerability in Specialk Simple Download Counter, classified under Cross-site Scripting. CVSS score: 6.4/10. Published 2026-03-26.
How severe is CVE-2026-4278?
Medium severity. CVSS v3 base score is 6.4 out of 10.