# CVE-2026-85538: MISP Attribute Deletion Authorization Bypass Allows Users Without Modify Permissions to Delete Attributes

> Authenticated users can delete event attributes without proper modification permissions, leading to unauthorized data loss in MISP threat intelligence platforms.

- **Severity:** High 8.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:H/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-9pvc-hwg3-vhmw

## What is CVE-2026-85538?

CVE-2026-85538 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 incorrect authorization vulnerability in MISP allowed authenticated users to delete attributes from events despite lacking the required perm_modify or perm_modify_org permissions.

The affected attribute deletion paths relied on organization membership checks performed by MispAttribute::deleteAttribute() but did not consistently enforce MISP's event modification authorization rules. Consequently, a user belonging to the organization associated with an event could potentially delete individual attributes or perform bulk attribute deletion even when their assigned role was not authorized to modify the event.

This created an inconsistency between attribute editing and deletion: editing an attribute correctly used MISP's ACL::canModifyEvent() authorization logic, whereas the affected deletion operations could bypass these permission checks.

An authenticated attacker with access to an affected MISP instance and membership in the organization owning an event could exploit this flaw to remove attributes from that event, potentially causing unauthorized modification or loss of threat intelligence data.

The patch introduces a common authorization check for all affected deletion paths. Before deletion, MISP now resolves the associated events and verifies that the current user is authorized to modify each event using the same authorization mechanism used by normal event and attribute modification operations.

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2026-85538?


## How do I fix CVE-2026-85538?

No fix has been published for CVE-2026-85538 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-85538 being exploited?

There is no known exploitation of CVE-2026-85538 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-85538 and fix it if it is affected.

What it is: CVE-2026-85538 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-2026-85538 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-2026-85538/ (Markdown: https://insights.sbomify.com/CVE-2026-85538/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-85538
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-85538
- OSV: https://osv.dev/vulnerability/CVE-2026-85538

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-85538/
Summaries are generated and may contain mistakes; the official description above is the record.