# CVE-2025-12813: Holiday class post calendar <= 7.1 - Unauthenticated Remote Code Execution via 'contents'

> Unauthenticated attackers can execute arbitrary code on the server via the contents parameter in the Holiday class post calendar plugin.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 11 Nov 2025
- **Updated:** 8 Apr 2026
- **Also known as:** GHSA-8h9p-5fxf-7jmx

## What is CVE-2025-12813?

CVE-2025-12813 is a critical code injection vulnerability in strix-bubol5 Holiday class post calendar, published on 11 Nov 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Holiday class post calendar plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 7.1 via the 'contents' parameter. This is due to a lack of sanitization of user-supplied data when creating a cache file. This makes it possible for unauthenticated attackers to execute code on the server.

Weakness: CWE-94 (Improper Control of Generation of Code)

## Which versions are affected by CVE-2025-12813?


## How do I fix CVE-2025-12813?

No fix has been published for CVE-2025-12813 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-12813 being exploited?

There is no known exploitation of CVE-2025-12813 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-12813 and fix it if it is affected.

What it is: CVE-2025-12813 is a critical code injection vulnerability in strix-bubol5 Holiday class post calendar, published on 11 Nov 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-12813 in the wild and no public exploit code.

Affected product: strix-bubol5 Holiday class post calendar. 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-2025-12813/ (Markdown: https://insights.sbomify.com/CVE-2025-12813/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-12813
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-12813
- OSV: https://osv.dev/vulnerability/CVE-2025-12813

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-12813/
Summaries are generated and may contain mistakes; the official description above is the record.