# CVE-2026-85533: MISP Sharing Group Authorization Bypass via Omitted Distribution Parameter

> Authenticated users can bypass Sharing Group authorization checks by omitting the distribution parameter, allowing unauthorized data association with restricted groups.

- **Severity:** High 7.6 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/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:** 4 Sep 2026
- **Updated:** 4 Sep 2026
- **Also known as:** GHSA-4pv3-xjc8-wfm8

## What is CVE-2026-85533?

CVE-2026-85533 is a high-severity missing authorization vulnerability in misp, published on 4 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

An authorization flaw in MISP allowed an authenticated user to submit a sharing_group_id without verifying that the user was authorized to use the referenced Sharing Group.

In several attribute and Galaxy Cluster creation and editing workflows, validation of the submitted Sharing Group was performed only when the request explicitly set the distribution field to 4 ("Sharing Group"). An attacker could therefore craft a request containing a sharing_group_id while omitting the distribution parameter, or otherwise avoiding the distribution == 4 condition, causing the Sharing Group authorization check to be skipped.

This could allow a user with permission to create or modify the affected MISP objects to associate data with a Sharing Group that they are not authorized to use. Depending on the affected object's existing distribution settings and subsequent processing, this could bypass intended information-sharing boundaries and result in unauthorized placement or distribution of data to members of another Sharing Group.

The issue affected attribute attachment and editing operations as well as Galaxy Cluster creation and editing. The fix ensures that authorization is performed whenever a non-empty sharing_group_id is submitted, independently of the distribution parameter. It also centralizes the authorization decision in SharingGroup::canUse() and explicitly rejects empty Sharing Group identifiers rather than allowing them to be interpreted as an unrestricted query.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2026-85533?


## How do I fix CVE-2026-85533?

No fix has been published for CVE-2026-85533 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-85533 being exploited?

There is no known exploitation of CVE-2026-85533 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-85533 and fix it if it is affected.

What it is: CVE-2026-85533 is a high-severity missing authorization vulnerability in misp, published on 4 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-2026-85533 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-2026-85533/ (Markdown: https://insights.sbomify.com/CVE-2026-85533/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-85533
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-85533
- OSV: https://osv.dev/vulnerability/CVE-2026-85533

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-85533/
Summaries are generated and may contain mistakes; the official description above is the record.