CVE-2026-21889: Weblate Weblate Leaks Information Vulnerability

LOW
Advisory Identifier: GHSA-3g2f-4rjg-9385
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CWE-284
Published
Advisory Summary

CVE-2026-21889 is a LOW weblate leaks information vulnerability (CWE-284: Improper Access Control) affecting Weblate libraries in the PyPI ecosystem. The issue involves weblate leaks information via screenshots. Remediation is available by upgrading affected packages to version 5.15.2.

CVE-2026-21889 at a Glance

CVE Identifier CVE-2026-21889
GHSA Identifier GHSA-3g2f-4rjg-9385
Severity LOW
CVSS v3.1 Base Score N/A
CWE Classification CWE-284: Improper Access Control
Affected Product Weblate
Package Ecosystem PyPI
Published Date
Last Updated

How to Fix CVE-2026-21889

To remediate this vulnerability, upgrade all affected Weblate 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: 5.15.2 
pip install weblate>=5.15.2
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-2026-21889, inspect your installed packages using pip:

pip show weblate

Analyze the terminal output to locate any version of Weblate in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 5.15.2), 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-284: Improper Access Control, where the product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. In Weblate, 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 The screenshot images were served directly by the HTTP server without proper access control. This could allow an unauthenticated user to access screenshots after guessing their filename. ### Patches * https://github.com/WeblateOrg/weblate/pull/17516 ### References Thanks to Lukas May and Michael Leu for reporting this.

CVE-2026-21889 Affected Weblate Versions

1 component(s)
Fixed Versions:
5.15.2
Product / Package Ecosystem Affected Versions Fixed Version
weblate
pypi/weblate
PyPI
< 5.15.2
5.15.2

References

GitHub Advisory / Wiki ADVISORY
https://github.com/WeblateOrg/weblate/security/advisories/GHSA-3g2f-4rjg-9385
NVD — CVE-2026-21889 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-21889
Weblate Source Repository REPOSITORY
https://github.com/WeblateOrg/weblate/pull/17516
Security Fix Commit FIX COMMIT
https://github.com/WeblateOrg/weblate/commit/a6eb5fd0299780eca286be8ff187dc2d10feec47
Weblate Source Repository REPOSITORY
https://github.com/WeblateOrg/weblate

Frequently Asked Questions

What is CVE-2026-21889?
CVE-2026-21889 is a security vulnerability in Weblate involving Weblate leaks information via screenshots under CWE-284: Improper Access Control.
Which Weblate versions are affected?
Affected versions include releases prior to 5.15.2 across affected packages: weblate.
What version fixes CVE-2026-21889?
Upgrading to 5.15.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is weblate affected?
Yes, weblate is affected in releases prior to 5.15.2. Upgrade your dependency to 5.15.2 or later.
What CWE is associated with CVE-2026-21889?
CVE-2026-21889 is classified under CWE-284: Improper Access Control (The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.).
How can I check PyPI dependencies for CVE-2026-21889?
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-3g2f-4rjg-9385",
  "modified" : "2026-01-14T19:50:09Z",
  "published" : "2026-01-14T16:45:07Z",
  "aliases" : [ "CVE-2026-21889" ],
  "summary" : "Weblate leaks information via screenshots",
  "details" : "### Impact\nThe screenshot images were served directly by the HTTP server without proper access control. This could allow an unauthenticated user to access screenshots after guessing their filename.\n\n### Patches\n* https://github.com/WeblateOrg/weblate/pull/17516\n\n### References\n\nThanks to Lukas May and Michael Leu for reporting this.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "weblate"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.15.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/WeblateOrg/weblate/security/advisories/GHSA-3g2f-4rjg-9385"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-21889"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/WeblateOrg/weblate/pull/17516"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/WeblateOrg/weblate/commit/a6eb5fd0299780eca286be8ff187dc2d10feec47"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/WeblateOrg/weblate"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-284" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-01-14T16:45:07Z",
    "nvd_published_at" : "2026-01-14T17:16:07Z"
  }
}