# CVE-2026-10855: MISP Event template importer authorization bypass

> Authenticated users can overwrite event templates owned by other organizations due to missing ownership checks, allowing unauthorized data modification.

- **Severity:** Medium 5.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 Jun 2026
- **Updated:** 4 Jun 2026
- **Also known as:** GHSA-243v-5f97-vfq3

## What is CVE-2026-10855?

CVE-2026-10855 is a medium-severity missing authorization vulnerability in Misp-Project Misp, published on 4 Jun 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

An authorization flaw existed in the MISP Event Template Importer overwrite workflow. When importing an event template in overwrite mode, the application checked whether a matching template already existed but did not verify that the importing user belonged to the organization that owned the existing template. As a result, an authenticated user with access to the template import functionality could forcibly overwrite an event template owned by another organization.

Successful exploitation could allow unauthorized modification of another organization’s event template, potentially altering template structure, attributes, or metadata used for subsequent event creation or sharing workflows. Site administrators are not affected by this restriction, as they are explicitly allowed to overwrite templates across organizations.

The issue was fixed by enforcing an ownership check before overwrite: non-site-admin users may only overwrite templates owned by their own organization.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2026-10855?

It affects 1 product.


Products: Misp-Project Misp.

## How do I fix CVE-2026-10855?

No fix has been published for CVE-2026-10855 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-10855 being exploited?

There is no known exploitation of CVE-2026-10855 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-2026-10855 and fix it if it is affected.

What it is: CVE-2026-10855 is a medium-severity missing authorization vulnerability in Misp-Project Misp, published on 4 Jun 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-10855 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-2026-10855/ (Markdown: https://insights.sbomify.com/CVE-2026-10855/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-10855
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-10855
- OSV: https://osv.dev/vulnerability/CVE-2026-10855

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-10855/
Summaries are generated and may contain mistakes; the official description above is the record.