File Reading Vulnerability in Flatpak Builder Tool by Flatpak
CVE-2026-39977

7.1HIGH

Key Information:

Vendor

Flatpak

Status
Flatpak-builder
Vendor
CVE Published:
9 April 2026

What is CVE-2026-39977?

The flatpak-builder tool, used to construct Flatpaks from source, has a vulnerability that allows crafted manifests to exploit user-defined license file paths. This flaw permits the reading of arbitrary files from the host system, as the tool does not adequately validate symlinks during the resolution process. Specifically, the checks applied do not ensure safety when resolving paths, leading to potential exposure of sensitive data in the build output. This issue affects versions from 1.4.5 up to, but not including, 1.4.8, and has been addressed in the latest update.

Affected Version(s)

flatpak-builder >= 1.4.5, < 1.4.8

References

https://github.com/flatpak/flatpak-builder/security/advis...
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CVSS V4

Score:
7.1
Severity:
HIGH
Confidentiality:
High
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • Vulnerability published

  • Vulnerability Reserved

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