CVE-2026-50127: Weblate SSRF Outbound URL Guard Misses Some Vulnerability

MODERATE
Advisory Identifier: GHSA-vmfc-9982-2m45
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CVSS 5.9
CWE-918
Published
Advisory Summary

CVE-2026-50127 is a MODERATE (CVSS 5.9) outbound url guard misses some vulnerability (CWE-918: Server-Side Request Forgery (SSRF)) affecting Weblate SSRF libraries in the PyPI ecosystem. The issue involves outbound url guard misses some private ranges. Remediation is available by upgrading affected packages to version 2026.6.

CVE-2026-50127 at a Glance

CVE Identifier CVE-2026-50127
GHSA Identifier GHSA-vmfc-9982-2m45
Severity MODERATE
CVSS v3.1 Base Score 5.9
CWE Classification CWE-918: Server-Side Request Forgery (SSRF)
Affected Product Weblate SSRF
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 5.9

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2026-50127

To remediate this vulnerability, upgrade all affected Weblate SSRF dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

weblate fixed: 2026.6 
pip install weblate>=2026.6
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show weblate

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-50127, inspect your installed packages using pip:

pip show weblate

Analyze the terminal output to locate any version of Weblate SSRF in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2026.6), your application is affected.

Note: The pip show weblate command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-918: Server-Side Request Forgery (SSRF), where the web server receives a url or similar request from an upstream component and retrieves the contents of this url, but it does not sufficiently ensure that the request is being sent to the expected destination. In Weblate SSRF, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact Weblate's `VCS_RESTRICT_PRIVATE` did not properly account for some transitional IPv6 ranges, multicast addresses, or some semi-private IPv4 ranges, which allowed some addresses to bypass private range restrictions. ### Patches * https://github.com/WeblateOrg/weblate/pull/19768 ### Resources The issue was reported by @tonghuaroot via GitHub, and the same user also provided the initial patch.

CVE-2026-50127 Affected Weblate SSRF Versions

1 component(s)
Fixed Versions:
2026.6
Product / Package Ecosystem Affected Versions Fixed Version
weblate
pypi/weblate
PyPI
≥ 5.15
< 2026.6
2026.6

References

GitHub Advisory / Wiki ADVISORY
https://github.com/WeblateOrg/weblate/security/advisories/GHSA-vmfc-9982-2m45
NVD — CVE-2026-50127 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-50127
Weblate SSRF Source Repository REPOSITORY
https://github.com/WeblateOrg/weblate/pull/19768
Weblate SSRF Source Repository REPOSITORY
https://github.com/WeblateOrg/weblate
Weblate SSRF Release RELEASE
https://github.com/WeblateOrg/weblate/releases/tag/weblate-2026.6

Frequently Asked Questions

What is CVE-2026-50127?
CVE-2026-50127 is a security vulnerability in Weblate SSRF involving outbound URL guard misses some private ranges under CWE-918: Server-Side Request Forgery (SSRF).
Which Weblate SSRF versions are affected?
Affected versions include releases prior to 2026.6 across affected packages: weblate.
What version fixes CVE-2026-50127?
Upgrading to 2026.6 (or the latest patched release for your respective branch) resolves the vulnerability.
Is weblate affected?
Yes, weblate is affected in releases prior to 2026.6. Upgrade your dependency to 2026.6 or later.
What is the CVSS score of CVE-2026-50127?
CVE-2026-50127 has a CVSS v3.1 base score of 5.9 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N.
What CWE is associated with CVE-2026-50127?
CVE-2026-50127 is classified under CWE-918: Server-Side Request Forgery (SSRF) (The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.).
How can I check PyPI dependencies for CVE-2026-50127?
Run the dependency tree command: 'pip show weblate'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-vmfc-9982-2m45",
  "modified" : "2026-07-07T23:46:33Z",
  "published" : "2026-07-07T23:46:33Z",
  "aliases" : [ "CVE-2026-50127" ],
  "summary" : "Weblate SSRF: outbound URL guard misses some private ranges",
  "details" : "### Impact\n\nWeblate's `VCS_RESTRICT_PRIVATE` did not properly account for some transitional IPv6 ranges, multicast addresses, or some semi-private IPv4 ranges, which allowed some addresses to bypass private range restrictions.\n\n### Patches\n\n* https://github.com/WeblateOrg/weblate/pull/19768\n\n### Resources\n\nThe issue was reported by @tonghuaroot via GitHub, and the same user also provided the initial patch.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "weblate"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "5.15"
      }, {
        "fixed" : "2026.6"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/WeblateOrg/weblate/security/advisories/GHSA-vmfc-9982-2m45"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-50127"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/WeblateOrg/weblate/pull/19768"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/WeblateOrg/weblate"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/WeblateOrg/weblate/releases/tag/weblate-2026.6"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-918" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-07T23:46:33Z",
    "nvd_published_at" : "2026-06-10T20:17:29Z"
  }
}