CVE-2026-77871
Post Snippets <= 4.2.4 - Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode Attributes
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.
INFO
Published Date :
Oct. 28, 2026, 7:16 a.m.
Last Modified :
Oct. 28, 2026, 7:16 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-77871
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | MITRE-CVE | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update the Post Snippets plugin to the latest version.
- Ensure snippet shortcodes are disabled if not needed.
- Apply security patches from the vendor.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-77871.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-77871 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-77871
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-77871 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-77871 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Oct. 28, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N Added CWE CWE-79 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/77xxx/CVE-2026-77871.json">CVE-2026-77871</a> Added Reference https://plugins.trac.wordpress.org/browser/post-snippets/tags/4.2.3/src/PostSnippets/Shortcode.php#L140 Added Reference https://plugins.trac.wordpress.org/browser/post-snippets/tags/4.2.3/src/PostSnippets/Shortcode.php#L183 Added Reference https://plugins.trac.wordpress.org/browser/post-snippets/tags/4.2.3/src/PostSnippets/Shortcode.php#L29 Added Reference https://plugins.trac.wordpress.org/browser/post-snippets/tags/4.2.3/src/PostSnippets/Shortcode.php#L70 Added Reference https://plugins.trac.wordpress.org/browser/post-snippets/tags/4.2.4/src/PostSnippets/Shortcode.php#L140 Added Reference https://plugins.trac.wordpress.org/browser/post-snippets/tags/4.2.4/src/PostSnippets/Shortcode.php#L183 Added Reference https://plugins.trac.wordpress.org/browser/post-snippets/tags/4.2.4/src/PostSnippets/Shortcode.php#L29 Added Reference https://plugins.trac.wordpress.org/browser/post-snippets/tags/4.2.4/src/PostSnippets/Shortcode.php#L70 Added Reference https://plugins.trac.wordpress.org/changeset/3759640/post-snippets/trunk/src/PostSnippets/Shortcode.php Added Reference https://www.wordfence.com/threat-intel/vulnerabilities/id/a46c37f4-245d-423f-bdad-296fdf377ecc?source=cve