# CVE-2026-3739: suitenumerique messages ThreadAccess serializers.py ThreadAccessSerializer improper authentication

> Improper authentication in ThreadAccessSerializer allows remote attackers to bypass access controls and access thread data.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P`)
- **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:** 8 Mar 2026
- **Updated:** 12 Mar 2026
- **Also known as:** GHSA-632x-p8x5-j45w, GHSA-7476-6crq-4cw9

## What is CVE-2026-3739?

CVE-2026-3739 is a medium-severity authentication bypass vulnerability in suitenumerique messages, published on 8 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A security flaw has been discovered in suitenumerique messages 0.2.0. This issue affects the function ThreadAccessSerializer of the file src/backend/core/api/serializers.py of the component ThreadAccess. The manipulation results in improper authentication. The attack can be executed remotely. The exploit has been released to the public and may be used for attacks. Upgrading to version 0.3.0 is capable of addressing this issue. The patch is identified as d7729f4b885449f6dee3faf8b5f2a05769fb3d6e. The affected component should be upgraded.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-3739?


## How do I fix CVE-2026-3739?

No fix has been published for CVE-2026-3739 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-3739 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-3739 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-3739 and fix it if it is affected.

What it is: CVE-2026-3739 is a medium-severity authentication bypass vulnerability in suitenumerique messages, published on 8 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-3739 exists.

Affected product: suitenumerique messages. 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-2026-3739/ (Markdown: https://insights.sbomify.com/CVE-2026-3739/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-3739
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-3739
- OSV: https://osv.dev/vulnerability/CVE-2026-3739

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-3739/
Summaries are generated and may contain mistakes; the official description above is the record.