# CVE-2026-77871: Post Snippets <= 4.2.4 - Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode Attributes


- **Severity:** Medium 6.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 28 Oct 2026
- **Updated:** 29 Oct 2026
- **Also known as:** GHSA-6hh4-5cgj-w743

## What is CVE-2026-77871?

CVE-2026-77871 is a medium-severity vulnerability in saadiqbal Post Snippets – Custom WordPress Code Snippets Customizer, published on 28 Oct 2026. 

### Official 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 &lt;script&gt;...&lt;/script&gt; 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.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-77871?


## How do I fix CVE-2026-77871?

No fix has been published for CVE-2026-77871 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-77871 being exploited?

There is no known exploitation of CVE-2026-77871 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-77871 and fix it if it is affected.

What it is: CVE-2026-77871 is a medium-severity vulnerability in saadiqbal Post Snippets – Custom WordPress Code Snippets Customizer, published on 28 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-77871 in the wild and no public exploit code.

Affected product: saadiqbal Post Snippets – Custom WordPress Code Snippets Customizer. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-77871/ (Markdown: https://insights.sbomify.com/CVE-2026-77871/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-77871
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-77871
- OSV: https://osv.dev/vulnerability/CVE-2026-77871

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-77871/
Summaries are generated and may contain mistakes; the official description above is the record.