# CVE-2026-78159: Code injection in The Events Calendar

> Unauthenticated attackers can execute arbitrary code on WordPress sites using The Events Calendar plugin if comments are enabled on event posts.

- **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:** 12 Sep 2026
- **Updated:** 14 Sep 2026
- **Also known as:** GHSA-9c57-9fxg-8x9j

## What is CVE-2026-78159?

CVE-2026-78159 is a critical code injection vulnerability in stellarwp The Events Calendar, published on 12 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The The Events Calendar plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 6.17.3 via the parse_array function. This is due to insufficient validation of the widget 'classes' map, allowing a plain-array payload to bypass the is_safe_widget_instance() object check and reach the callable-invocation sink in Element_Classes::parse_array(). This makes it possible for unauthenticated attackers to execute code on the server. Exploitation requires that the targeted site has comments enabled on tribe_events posts and that at least one comment containing a crafted wp:legacy-widget block has been submitted, as the attack chain is triggered when do_blocks() processes the single-event HTML including the comment area.

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

## Which versions are affected by CVE-2026-78159?


## How do I fix CVE-2026-78159?

No fix has been published for CVE-2026-78159 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-78159 being exploited?

There is no known exploitation of CVE-2026-78159 in the wild and no public exploit code.

Public exploit code:

- CVE-2026-78159 - stellarwp - Critical 9.8 - Unauthenticated POST /wp-comments-post.php - Remote Code Execution (github_poc): https://github.com/abraxas/CVE-2026-78159

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-78159 and fix it if it is affected.

What it is: CVE-2026-78159 is a critical code injection vulnerability in stellarwp The Events Calendar, published on 12 Sep 2026. 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-2026-78159 in the wild and no public exploit code.

Affected product: stellarwp The Events 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-2026-78159/ (Markdown: https://insights.sbomify.com/CVE-2026-78159/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-78159
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-78159
- OSV: https://osv.dev/vulnerability/CVE-2026-78159

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-78159/
Summaries are generated and may contain mistakes; the official description above is the record.