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CVE-2026-120477 webguyio stop spammers classic: Cross-site Scripting

4.7 mediumEPSS 0.3%

Medium (4.7) in webguyio stop spammers classic. EPSS 0.3% estimated probability of exploitation activity in the next 30 days.

On this page
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.

Severity

CVSS 3.1

4.7 medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
EPSS
0.3% estimated probability of exploitation activity in the next 30 days; 17th percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
CISA's assessment (SSVC)
Exploitation: none · Automatable: no · Technical impact: partial, assessed 2026-11-07. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
CWE
CWE-79 Improper Neutralization of Input During Web Page Generation (Cross-site Scripting)
OWASP Top 10
A05:2025 Injection
Published
Modified
NVD analysis
Deferred: the NVD does not plan to analyze it
Record from
the NVD, synced

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CVE-2026-120477

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Affected

  • webguyio:stop spammers classic

Versions

From the CNA's record in the CVE List.

ProductAffected
webguyio Stop Spammers Classicthrough 2026.6

Attack patterns (CAPEC)

  • CAPEC-63 Cross-Site Scripting (XSS) Likelihood: High · Severity: Very High
  • CAPEC-85 AJAX Footprinting Likelihood: High · Severity: Low
  • CAPEC-209 XSS Using MIME Type Mismatch Severity: Medium
  • CAPEC-588 DOM-Based XSS Likelihood: High · Severity: Very High
  • CAPEC-591 Reflected XSS Likelihood: High · Severity: Very High
  • CAPEC-592 Stored XSS Likelihood: High · Severity: Very High

The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.

References

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