Flatpak: flatpak: world-writable temporary child repositories in system-helper cache path
Summary
| CVE | CVE-2026-97026 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-28 21:17:19 UTC |
| Updated | 2026-09-28 21:17:19 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 3.9 LOW from [email protected]
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:L
Problem Types: CWE-378 | CWE-378 Creation of Temporary File With Insecure Permissions
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 3.9 | LOW | CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:L |
| 3.1 | CNA | CVSS | 3.9 | LOW | CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:L |
CVSS v3.1 Breakdown
Attack Vector
LocalAttack Complexity
LowPrivileges Required
LowUser Interaction
RequiredScope
UnchangedConfidentiality
LowIntegrity
NoneAvailability
LowCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:L
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Red Hat | Red Hat Enterprise Linux 10 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 7 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 8 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 9 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| access.redhat.com/security/cve/CVE-2026-97026 | [email protected] | access.redhat.com | |
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | |
| github.com/flatpak/flatpak/security/advisories/GHSA-r9w3-qx54-qvc8 | [email protected] | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Red Hat would like to thank AISLE for reporting this issue. (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-09-28T13:28:31.000Z | Reported to Red Hat. |
| CNA | 2026-09-28T13:28:31.000Z | Made public. |
Workarounds
CNA: Set a umask that does not allow other users to write to the cache directory, for example: umask 022. Note that a umask that does not allow read/exec access by all (for example 027 or 077) will prevent the flatpak-system-helper from reading the temporary directory directly, resulting in falling back to copying the repository inefficiently, with a warning.
There are currently no legacy QID mappings associated with this CVE.