Weblate: Prefix-Based Repository Boundary Check Bypass via Symlink/Junction Path Prefix Collision

CVE-2026-40256 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

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 for reporting this issue via HackerOne.

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2026-04-16 21:08:47 UTC
Updated
2026-04-16 21:08:47 UTC
GitHub reviewed
2026-04-16 21:08:47 UTC
NVD published
2026-04-15

EPSS Score

Score Percentile
0.04% 11.93%

CVSS Scores

Base score Version Severity Vector
5.0 3.1 —
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.

Identifiers

Type Value
GHSA GHSA-ffgh-3jrf-8wvh ↗
CVE CVE-2026-40256 ↗

CWEs

CWE id Name
CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Credits

  • nijel (remediation_developer)
  • M9nx (reporter)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
pip weblate < 5.17 5.17 —

References

cvelogic Threat Intelligence