CVE-2026-34078
CRITICALEPSS 76th pctlDescription
Flatpak is a Linux application sandboxing and distribution framework. Prior to 1.16.4, the Flatpak portal accepts paths in the sandbox-expose options which can be app-controlled symlinks pointing at arbitrary paths. Flatpak run mounts the resolved host path in the sandbox. This gives apps access to all host files and can be used as a primitive to gain code execution in the host context. This vulnerability is fixed in 1.16.4.
How to fix
This Red Hat / RHEL release reached end-of-life on 2024-06-30. Extended security maintenance is available until 2029-05-31.
This Red Hat / RHEL release reached end-of-life on 2024-06-30. Extended security maintenance is available until 2029-05-31.
This Red Hat / RHEL release reached end-of-life on 2024-06-30. Extended security maintenance is available until 2029-05-31.
This Red Hat / RHEL release reached end-of-life on 2024-06-30. Extended security maintenance is available until 2029-05-31.
This vulnerability affects an unusually large number of packages. The highest-confidence fixes are shown above; the full list is longer. Check the referenced advisories for complete coverage.
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Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Exploit Intelligence
Elevated risk: more likely to be exploited than 76% of all known CVEs.
References
Related Vulnerabilities
Other CWE-61 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2024-28189 | Critical | 10.0 | 7.2% | - | - |
| CVE-2024-28185 | Critical | 10.0 | 7.1% | - | - |
| CVE-2019-11249 | Medium | 6.5 | 3.7% | - | Fix |
| CVE-2019-11246 | Medium | 6.5 | 3.6% | - | Fix |
| CVE-2019-16775 | High | 7.7 | 3.3% | - | Fix |
| CVE-2019-11251 | Medium | 4.8 | 2.6% | - | Fix |
Common questions
How do I fix CVE-2026-34078?
Published advisories record a fix for 37 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.
Is CVE-2026-34078 being actively exploited?
Not that we know of. CVE-2026-34078 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 1.7% is the estimated probability that it will be exploited in the next 30 days. That is higher than 76% of all scored CVEs.
How severe is CVE-2026-34078?
CVE-2026-34078 has a CVSS v3 base score of 10.0, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-34078 affect?
Published advisories record a fix for flatpak (Amazon), flatpak-builder (Amazon), flatpak-debuginfo (Amazon), flatpak-debugsource (Amazon), and 33 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-07-24.