weblate up to 5.16 repo_outside path traversal

Summaryinfo

A vulnerability was found in weblate up to 5.16. It has been classified as critical. This impacts the function repo_outside. This manipulation causes path traversal. This vulnerability is tracked as CVE-2026-40256. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability has been found in weblate up to 5.16 and classified as critical. Affected by this vulnerability is the function repo_outside. The manipulation with an unknown input leads to a path traversal vulnerability. The CWE definition for the vulnerability is CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. As an impact it is known to affect confidentiality. The summary by CVE is:

Weblate is a web based localization tool. In versions prior to 5.17, 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). This issue has been fixed in version 5.17.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-40256 since 04/10/2026. The exploitation appears to be easy. The attack can be launched remotely. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1006 for this issue.

Upgrading to version 5.17 eliminates this vulnerability. Applying the patch e30dbcb33ae78e754ecef192d54f996b89cb4e15 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

• weblate

Version

• 5.0
• 5.1
• 5.2
• 5.3
• 5.4
• 5.5
• 5.6
• 5.7
• 5.8
• 5.9
• 5.10
• 5.11
• 5.12
• 5.13
• 5.14
• 5.15
• 5.16

License

• open-source

CPE 2.3info

• 🔒
• 🔒
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CPE 2.2info

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• 🔒
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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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