GHSA-FFGH-3JRF-8WVH

Vulnerability from github – Published: 2026-04-16 21:08 – Updated: 2026-04-16 21:08
VLAI?
Summary
Weblate: Prefix-Based Repository Boundary Check Bypass via Symlink/Junction Path Prefix Collision
Details

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.

Severity ?
5.0 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "weblate"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5.17"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-40256"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-16T21:08:47Z",
    "nvd_published_at": "2026-04-15T19:16:37Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\nWeblate 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).\n\n### Patches\n* https://github.com/WeblateOrg/weblate/pull/18847\n\n### References\nThanks to [m9nx4u](https://hackerone.com/m9nx4u) for reporting this issue via HackerOne.",
  "id": "GHSA-ffgh-3jrf-8wvh",
  "modified": "2026-04-16T21:08:47Z",
  "published": "2026-04-16T21:08:47Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/WeblateOrg/weblate/security/advisories/GHSA-ffgh-3jrf-8wvh"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-40256"
    },
    {
      "type": "WEB",
      "url": "https://github.com/WeblateOrg/weblate/pull/18847"
    },
    {
      "type": "WEB",
      "url": "https://github.com/WeblateOrg/weblate/commit/e30dbcb33ae78e754ecef192d54f996b89cb4e15"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/WeblateOrg/weblate"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Weblate: Prefix-Based Repository Boundary Check Bypass via Symlink/Junction Path Prefix Collision"
}


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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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