CVE-2026-97026: Flatpak: flatpak: world-writable temporary child repositories in system-helper cache path
Vulnerability summary
CVE-2026-97026 is a low (CVSS 3.9) vulnerability in flatpak. EPSS estimates a 0.11% chance of exploitation in the next 30 days, higher than 1.1% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 2 · Related 1Timeline
- 28-09-2026PublishedVulnerability first disclosed.
- 30-09-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
4 scores · 4 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated3.9LowCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:L
- OSV · DebianEcosystem advisory · calculated3.9LowCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:L
- NVDNIST3.9LowCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:L
EPSS trend
Probability
0.11%
Chance of exploitation in the next 30 days
Percentile
1%
Versus all other CVEs
30-day change
Change unavailable
Change unavailable
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Debian1 product
- flatpakAll versions (No fix recorded) | < 1.16.6-1~deb13u3 | < 1.18.4-1
Ubuntu1 product
- flatpakAll versions (No fix recorded)
2 vendors · 2 products
