CVE-2026-77871 json
Post Snippets <= 4.2.4 - Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode Attributes
published 2026-10-28 12 d ago modified 2026-10-29 11 d ago also EUVD-2026-111606
- cvss
- 6.4
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 15%
- public exploits
- 0
- none known
Summary
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.
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 11 d ago
Exploit prediction
0.24% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N |
Affected products
- saadiqbal Post Snippets – Custom WordPress Code Snippets Customizer
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
- Technology feeds
References
- wordfence.com /threat-intel/vulnerabilities/id/a46c37f4-245d-423f-bdad-296fdf377ecc?source=cve
- plugins.trac.wordpress.org /browser/post-snippets/tags/4.2.3/src/PostSnippets/Shortcode.php#L183
- plugins.trac.wordpress.org /browser/post-snippets/tags/4.2.4/src/PostSnippets/Shortcode.php#L183
- plugins.trac.wordpress.org /browser/post-snippets/tags/4.2.4/src/PostSnippets/Shortcode.php#L140
- plugins.trac.wordpress.org /browser/post-snippets/tags/4.2.4/src/PostSnippets/Shortcode.php#L70
- plugins.trac.wordpress.org /browser/post-snippets/tags/4.2.4/src/PostSnippets/Shortcode.php#L29
- plugins.trac.wordpress.org /browser/post-snippets/tags/4.2.3/src/PostSnippets/Shortcode.php#L140
- plugins.trac.wordpress.org /browser/post-snippets/tags/4.2.3/src/PostSnippets/Shortcode.php#L70
- plugins.trac.wordpress.org /browser/post-snippets/tags/4.2.3/src/PostSnippets/Shortcode.php#L29
- plugins.trac.wordpress.org /changeset/3759640/post-snippets/trunk/src/PostSnippets/Shortcode.php
Sources
- CVE List CVE-2026-77871
- NVD CVE-2026-77871
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.