CVE-2026-93847 Improper post type validation on scheduled post endpoints
Low 3.5
Published
Updated
Check this codebase for CVE-2026-93847 and fix it if it is affected.
What it is: CVE-2026-93847 is a low-severity vulnerability in Mattermost, published on 26 Oct 2026.
Exploitation: There is no known exploitation of CVE-2026-93847 in the wild and no public exploit code.
Affected product: Mattermost. 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-2026-93847/ (Markdown: https://insights.sbomify.com/CVE-2026-93847/index.md)
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-93847?
CVE-2026-93847 is a low-severity vulnerability in Mattermost, published on 26 Oct 2026.
Official description
Mattermost versions 11.7.x <= 11.7.10 fail to validate reserved system post types on the scheduled post creation and publication paths which allows an authenticated channel member to publish messages rendering as trusted system events via the scheduled post endpoint.. Mattermost Advisory ID: MMSA-2026-00732
Weakness: CWE-863
Which versions are affected by CVE-2026-93847?
How do I fix CVE-2026-93847?
No fix has been published for CVE-2026-93847 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-93847 being exploited?
There is no known exploitation of CVE-2026-93847 in the wild and no public exploit code.
Sources
Also known as GHSA-8jc7-6qx5-pfvj.