CVE-2026-77871
Received Received - Intake

Stored XSS in Post Snippets WordPress Plugin

Publication date: 2026-10-28

Last updated on: 2026-10-28

Assigner: Wordfence

Description
The Post Snippets – Custom WordPress Code Snippets Customizer plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Shortcode Attributes in all versions up to, and including, 4.2.4 due to insufficient input sanitization and output escaping. 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. Entity-encoded payloads such as <script>...</script> survive WordPress's wp_kses_post on-save sanitization because kses does not decode HTML entities, and are only converted back into executable HTML tags at render time by the plugin's own shortcode filter. This requires snippet shortcodes to be enabled.

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Meta Information

Published
2026-10-28
Last Modified
2026-10-28
Generated
2026-10-28
AI Q&A
2026-10-28
EPSS Evaluated
N/A
NVD
CVE-2026-77871
EUVD
EUVD-2026-111606

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
saadiqbal Post Snippets – Custom WordPress Code Snippets Customizer 0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-79 The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

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Executive Summary

This vulnerability is a Stored Cross-Site Scripting (XSS) flaw in the Post Snippets WordPress plugin up to version 4.2.4. It occurs due to insufficient input sanitization and output escaping in shortcode attributes. Authenticated attackers with contributor-level access or higher can inject malicious scripts into pages via specially crafted shortcodes. These scripts execute when users view the affected pages.

Detection Guidance

To detect this vulnerability, inspect WordPress sites using the Post Snippets plugin for suspicious shortcode usage. Check for encoded scripts like <script> in snippet content or database entries. Review user roles with contributor access or higher for unauthorized snippet creation.

Impact Analysis

If exploited, this vulnerability allows attackers to steal user sessions, perform actions on behalf of users, or deface websites. It may also lead to further malware infections or phishing attacks. Users with contributor-level access or higher on a WordPress site using the vulnerable plugin are at risk of exploiting this flaw.

Compliance Impact

This vulnerability could lead to unauthorized data access or modification, violating GDPR's integrity and confidentiality principles. For HIPAA, it may risk protected health information exposure. Compliance failures could result in legal penalties, reputational damage, and loss of trust.

Mitigation Strategies

Update the Post Snippets plugin to the latest version beyond 4.2.4 to patch the vulnerability. Disable snippet shortcodes if not in use. Review user roles with contributor-level access and above for unauthorized code snippets.

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