CVE-2026-40256
Weblate: Prefix-Based Repository Boundary Check Bypass via Symlink/Junction Path Prefix Collision
Description
### Impact Weblate repository-boundary validation relies on string prefix checks on resolved absolute paths. In multiple code paths, the check uses startswith against the repository root path. This is not path-segment aware and can be bypassed when the external path shares the same string prefix as the repository path (for example, repo and repo_outside). ### Patches * https://github.com/WeblateOrg/weblate/pull/18847 ### References Thanks to [m9nx4u](https://hackerone.com/m9nx4u) for reporting this issue via HackerOne.
How to fix CVE-2026-40256
To remediate CVE-2026-40256, upgrade the affected package to a fixed version below.
- —upgrade to 5.17 or later
Is CVE-2026-40256 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0, < 5.17
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM5.0 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N |