# CVE-2026-85236: MISP cullEmptyEvents CSRF Allows Irreversible Deletion of Events via GET Request

> An attacker can trick authenticated MISP users into deleting published empty events via a crafted GET request, causing irreversible data loss.

- **Severity:** High 8.8 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 3 Sep 2026
- **Updated:** 5 Sep 2026
- **Also known as:** GHSA-h2cm-43wh-hxvc

## What is CVE-2026-85236?

CVE-2026-85236 is a high-severity vulnerability in Misp-Project Misp, published on 3 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A cross-site request forgery (CSRF) vulnerability existed in the cullEmptyEvents action of MISP. The endpoint performed a state-changing and irreversible operation while accepting HTTP GET requests.

Because bodyless GET requests are not subject to CakePHP's CSRF validation, an attacker could cause an authenticated MISP user with sufficient privileges to invoke the endpoint simply by causing their browser to load a crafted URL, for example through an embedded image or other automatically requested resource.

Successful exploitation triggers the deletion of published empty events. The deletion is particularly significant because the operation uses skipBlocklist, meaning the removed events do not leave blocklist entries that could prevent or track their subsequent synchronization. This can result in unintended and potentially irreversible deletion of MISP event records without explicit user interaction.

The vulnerability was addressed by restricting cullEmptyEvents to HTTP POST requests, ensuring that CakePHP's normal CSRF protections are applied to the operation.

Weakness: CWE-352 (Cross-Site Request Forgery)

## Which versions are affected by CVE-2026-85236?

It affects 1 product.


Products: Misp-Project Misp.

## How do I fix CVE-2026-85236?

No fix has been published for CVE-2026-85236 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-85236 being exploited?

There is no known exploitation of CVE-2026-85236 in the wild and no public exploit code.

## Other vulnerabilities in Misp-Project Misp

- [CVE-2024-46918](https://insights.sbomify.com/CVE-2024-46918/): Missing authorization in n/a (critical 9.8)
- [CVE-2024-45509](https://insights.sbomify.com/CVE-2024-45509/): Missing authorization in n/a (critical 9.8)
- [CVE-2024-29858](https://insights.sbomify.com/CVE-2024-29858/): File upload in n/a (critical 9.8)
- [CVE-2024-29859](https://insights.sbomify.com/CVE-2024-29859/): File upload in n/a (critical 9.8)
- [CVE-2024-25674](https://insights.sbomify.com/CVE-2024-25674/): File upload in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-85236 and fix it if it is affected.

What it is: CVE-2026-85236 is a high-severity vulnerability in Misp-Project Misp, published on 3 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-2026-85236 in the wild and no public exploit code.

Affected product: Misp-Project Misp. 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-2026-85236/ (Markdown: https://insights.sbomify.com/CVE-2026-85236/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-85236
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-85236
- OSV: https://osv.dev/vulnerability/CVE-2026-85236

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-85236/
Summaries are generated and may contain mistakes; the official description above is the record.