# CVE-2026-91846: MISP Collection Element Add Missing Authorization on Referenced Object UUID

> Attackers can create collection elements referencing private objects via UUIDs, leading to unauthorized disclosure of sensitive data.

- **Severity:** High 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Sep 2026
- **Updated:** 15 Sep 2026
- **Also known as:** GHSA-wg2v-97w4-3m8g

## What is CVE-2026-91846?

CVE-2026-91846 is a high-severity missing authorization vulnerability in MISP, published on 15 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Affected versions of MISP allow a collection element to be created from a bare UUID without consistently checking whether the acting user is allowed to access the referenced object.

The commit explains that collection elements themselves only store UUIDs, while the collection view later resolves those UUIDs into their underlying objects. Before this fix, the generic add() path could therefore persist a UUID for an Event or Galaxy Cluster that the caller could not normally read. The patch explicitly notes that this made collections a way to reference another organisation’s private data and had caused disclosure of organisation-only events in the beta collection view.

The fix centralizes authorization in __assertCanUseElements(). Event UUIDs are validated through Event::fetchSimpleEvent() under the current user’s ACL, while Galaxy Cluster UUIDs are checked through GalaxyCluster::fetchGalaxyClusters(). The check is applied both to the CRUD add() path and to addElementToCollection().

Version affected: ≤2.5.45

Weakness: CWE-862 (Missing Authorization), CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-91846?


## How do I fix CVE-2026-91846?

No fix has been published for CVE-2026-91846 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-91846 being exploited?

There is no known exploitation of CVE-2026-91846 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-91846 and fix it if it is affected.

What it is: CVE-2026-91846 is a high-severity missing authorization vulnerability in MISP, published on 15 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-91846 in the wild and no public exploit code.

Affected product: 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-2026-91846/ (Markdown: https://insights.sbomify.com/CVE-2026-91846/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-91846
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-91846
- OSV: https://osv.dev/vulnerability/CVE-2026-91846

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-91846/
Summaries are generated and may contain mistakes; the official description above is the record.