GHSA-HFPV-MC5V-P9MM
Vulnerability from github – Published: 2026-05-26 16:41 – Updated: 2026-05-26 16:41Impact
The Create Component functionality in Weblate allows authorized users to add new translation components by specifying both a version control system and a source code repository URL to pull from. However, the repository URL field is not validated or sanitized, allowing an attacker to supply arbitrary protocols, hostnames, and IP addresses, including localhost, internal network addresses, and local filenames.
When the Mercurial version control system is selected, Weblate exposes the full server-side HTTP response for the provided URL. This effectively creates a server-side request forgery (SSRF) primitive that can probe internal services and return their contents. In addition to accessing internal HTTP endpoints, the behavior also enables local file enumeration by attempting file:// requests. While file contents may not always be returned, the application’s error messages clearly differentiate between files that exist and files that do not, revealing information about the server’s filesystem layout.
In cloud environments, this behavior is particularly dangerous, as internal-only endpoints such as cloud metadata services may be accessible, potentially leading to credential disclosure and full environment compromise.
Patches
This has been addressed in the Weblate 5.15 release.
- https://github.com/WeblateOrg/weblate/pull/17103
- https://github.com/WeblateOrg/weblate/pull/17102
Workarounds
Removing Mercurial from VCS_BACKENDS avoids this vulnerability, as the Git backend is not affected. The Git backend was already configured to block the file protocol and does not expose the HTTP response content in the error message.
References
Thanks to Jason Marcello for responsible disclosure.
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "Weblate"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "5.15"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2025-66407"
],
"database_specific": {
"cwe_ids": [
"CWE-352",
"CWE-918"
],
"github_reviewed": true,
"github_reviewed_at": "2026-05-26T16:41:13Z",
"nvd_published_at": "2025-12-16T00:16:02Z",
"severity": "MODERATE"
},
"details": "### Impact\nThe Create Component functionality in Weblate allows authorized users to add new translation components by specifying both a version control system and a source code repository URL to pull from. However, the repository URL field is not validated or sanitized, allowing an attacker to supply arbitrary protocols, hostnames, and IP addresses, including localhost, internal network addresses, and local filenames.\n\nWhen the Mercurial version control system is selected, Weblate exposes the full server-side HTTP response for the provided URL. This effectively creates a server-side request forgery (SSRF) primitive that can probe internal services and return their contents. In addition to accessing internal HTTP endpoints, the behavior also enables local file enumeration by attempting file:// requests. While file contents may not always be returned, the application\u2019s error messages clearly differentiate between files that exist and files that do not, revealing information about the server\u2019s filesystem layout.\n\n\n\nIn cloud environments, this behavior is particularly dangerous, as internal-only endpoints such as cloud metadata services may be accessible, potentially leading to credential disclosure and full environment compromise.\n\n### Patches\n\nThis has been addressed in the Weblate 5.15 release.\n\n* https://github.com/WeblateOrg/weblate/pull/17103\n* https://github.com/WeblateOrg/weblate/pull/17102\n\n### Workarounds\n\nRemoving Mercurial from [VCS_BACKENDS](https://docs.weblate.org/en/latest/admin/config.html#vcs-backends) avoids this vulnerability, as the Git backend is not affected. The Git backend was already configured to block the file protocol and does not expose the HTTP response content in the error message.\n\n### References\nThanks to Jason Marcello for responsible disclosure.",
"id": "GHSA-hfpv-mc5v-p9mm",
"modified": "2026-05-26T16:41:13Z",
"published": "2026-05-26T16:41:13Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/WeblateOrg/weblate/security/advisories/GHSA-hfpv-mc5v-p9mm"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-66407"
},
{
"type": "WEB",
"url": "https://github.com/WeblateOrg/weblate/pull/17102"
},
{
"type": "WEB",
"url": "https://github.com/WeblateOrg/weblate/pull/17103"
},
{
"type": "PACKAGE",
"url": "https://github.com/WeblateOrg/weblate"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/weblate/PYSEC-2025-231.yaml"
}
],
"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 has a Server-Side Request Forgery issue"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.