# CVE-2026-97026: Flatpak: flatpak: world-writable temporary child repositories in system-helper cache path

> Local attackers can cause denial of service by tampering with world-writable temporary Flatpak directories on multi-user systems with permissive umask settings.

- **Severity:** Low 3.9 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 28 Sep 2026
- **Updated:** 30 Sep 2026
- **Also known as:** DEBIAN-CVE-2026-97026, UBUNTU-CVE-2026-97026

## What is CVE-2026-97026?

CVE-2026-97026 is a low-severity vulnerability in Red Hat Enterprise Linux 10, published on 28 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

Flatpak creates temporary child repository directories under the user cache with world-writable permissions (0777). On multi-user systems with a permissive umask, other local users could read or modify the temporary directory used while installing apps or runtimes, potentially causing installation failures (denial of service); tampered content would fail signature/digest verification rather than being trusted.

Weakness: CWE-378 (Creation of Temporary File With Insecure Permissions)

## Which versions are affected by CVE-2026-97026?


## How do I fix CVE-2026-97026?

Apply the vendor's patch.

## Is CVE-2026-97026 being exploited?

There is no known exploitation of CVE-2026-97026 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-97026 and fix it if it is affected.

What it is: CVE-2026-97026 is a low-severity vulnerability in Red Hat Enterprise Linux 10, published on 28 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-97026 in the wild and no public exploit code.

Affected product: Red Hat Enterprise Linux 10. 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-2026-97026/ (Markdown: https://insights.sbomify.com/CVE-2026-97026/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-97026
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-97026
- OSV: https://osv.dev/vulnerability/CVE-2026-97026

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-97026/
Summaries are generated and may contain mistakes; the official description above is the record.