CVE-2026-120477: XSS (CVSS 4.7)

Description

The Stop Spammers Classic plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'author' POST parameter in versions up to, and including, 2026.6. An unauthenticated POST handled on init stores the attacker-supplied author field (after sanitize_text_field, which does not escape single quotes) into the ss_stop_sp_reg_stats option history. The Log Report admin page then renders that stored value inside a single-quoted JavaScript string within a double-quoted onclick attribute using esc_js(); because esc_js() uses _wp_specialchars with ENT_COMPAT it does not escape single quotes, allowing the stored value to break out of the JS string literal and inject arbitrary JavaScript. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute whenever an administrator with manage_options access clicks the 'Report to SFS' link on an attacker-poisoned log row (the StopForumSpam API key must be configured for that link to be rendered — the field is empty by default). Successful exploitation additionally requires an action by an administrator — the attacker cannot trigger the vulnerability on their own.

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CVSS v3.1 Score

4.7

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0025

Probability of exploitation

0.17%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

Frequently Asked Questions

What is CVE-2026-120477? +

The Stop Spammers Classic plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'author' POST parameter in versions up to, and including, 2026.6. An unauthenticated POST handled on init stores the attacker-supplied author field (after sanitize_text_field, which does not escape single quotes) into the ss_stop_sp_reg_stats option history. The Log Report admin page then renders that stored value inside a single-quoted JavaScript string within a double-quoted onclick attribute using esc_js(); because esc_js() uses _wp_specialchars with ENT_COMPAT it does not escape single quotes, allowing the stored value to break out of the JS string literal and inject arbitrary JavaScript. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute whenever an administrator with manage_options access clicks the 'Report to SFS' link on an attacker-poisoned log row (the StopForumSpam API key must be configured for that link to be rendered — the field is empty by default). Successful exploitation additionally requires an action by an administrator — the attacker cannot trigger the vulnerability on their own. It has a CVSS v3.1 base score of 4.7 (MEDIUM).

How severe is CVE-2026-120477? +

CVE-2026-120477 has a CVSS v3.1 score of 4.7 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0025, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-120477? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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