USN-8741-1: Flatpak vulnerabilities
It was discovered that Flatpak did not properly validate paths in sandbox-expose options. A malicious or compromised Flatpak app could use app-controlled symlinks to access arbitrary host files and gain code execution in the host context. This issue was addressed in Ubuntu Ubuntu 20.04 LTS, Ubuntu 22.04 LTS and Ubuntu 24.04 LTS. (CVE-2026-34078) It was discovered that Flatpak did not properly validate paths when removing outdated ld.so cache files. A malicious or compromised Flatpak app could use this issue to delete arbitrary files on the host. (CVE-2026-34079)
Details
Original advisory: https://ubuntu.com/security/notices/USN-8741-1
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Moderate exploitation riskCVE-2026-340781.7% 30-day exploitation probability. Patch within normal cadence, watch for KEV listing. Riskier than 76% of all EPSS-scored CVEs.
- Low exploitation riskCVE-2026-340790.32% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 25% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-34078 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-34079 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
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