CVE-2026-33220: Weblate JavaScript Localization CDN Add-on Allows Vulnerability

MODERATE
Advisory Identifier: GHSA-mqph-7h49-hqfm
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CVSS 6.8
CWE-200 CWE-22
Published
Advisory Summary

CVE-2026-33220 is a MODERATE (CVSS 6.8) javascript localization cdn add-on allows vulnerability (CWE-200: Exposure of Sensitive Information to an Unauthorized Actor) affecting Weblate libraries in the PyPI ecosystem. The issue involves javascript localization cdn add-on allows arbitrary local file read outside the repository. Remediation is available by upgrading affected packages to version 5.17.

CVE-2026-33220 at a Glance

CVE Identifier CVE-2026-33220
GHSA Identifier GHSA-mqph-7h49-hqfm
Severity MODERATE
CVSS v3.1 Base Score 6.8
CWE Classification CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
Affected Product Weblate
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 6.8

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

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

How to Fix CVE-2026-33220

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: 5.17 
pip install Weblate>=5.17
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-2026-33220, 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 5.17), 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-200: Exposure of Sensitive Information to an Unauthorized Actor, where the product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. 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 translation memory API exposed unintended endpoints, which in turn didn't do proper access control. ### Patches * https://github.com/WeblateOrg/weblate/pull/18516 ### Workarounds The CDN add-on is not enabled by default. ### References Thanks to @spbavarva for reporting this responsibly via GitHub.

CVE-2026-33220 Affected Weblate Versions

1 component(s)
Fixed Versions:
5.17
Product / Package Ecosystem Affected Versions Fixed Version
Weblate
pypi/Weblate
PyPI
< 5.17
5.17

References

GitHub Advisory / Wiki ADVISORY
https://github.com/WeblateOrg/weblate/security/advisories/GHSA-mqph-7h49-hqfm
NVD — CVE-2026-33220 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33220
Weblate Source Repository REPOSITORY
https://github.com/WeblateOrg/weblate/pull/18516
Weblate Source Repository REPOSITORY
https://github.com/WeblateOrg/weblate
Weblate Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/weblate/PYSEC-2026-153.yaml

Frequently Asked Questions

What is CVE-2026-33220?
CVE-2026-33220 is a security vulnerability in Weblate involving JavaScript localization CDN add-on allows arbitrary local file read outside the repository under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor.
Which Weblate versions are affected?
Affected versions include releases prior to 5.17 across affected packages: Weblate.
What version fixes CVE-2026-33220?
Upgrading to 5.17 (or the latest patched release for your respective branch) resolves the vulnerability.
Is Weblate affected?
Yes, Weblate is affected in releases prior to 5.17. Upgrade your dependency to 5.17 or later.
What is the CVSS score of CVE-2026-33220?
CVE-2026-33220 has a CVSS v3.1 base score of 6.8 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:N.
What CWE is associated with CVE-2026-33220?
CVE-2026-33220 is classified under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor (The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.).
How can I check PyPI dependencies for CVE-2026-33220?
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-mqph-7h49-hqfm",
  "modified" : "2026-06-08T19:54:08Z",
  "published" : "2026-04-16T20:41:29Z",
  "aliases" : [ "CVE-2026-33220" ],
  "summary" : "Weblate: JavaScript localization CDN add-on allows arbitrary local file read outside the repository",
  "details" : "### Impact\nThe translation memory API exposed unintended endpoints, which in turn didn't do proper access control.\n\n### Patches\n* https://github.com/WeblateOrg/weblate/pull/18516\n\n### Workarounds\nThe CDN add-on is not enabled by default.\n\n### References\nThanks to @spbavarva for reporting this responsibly via GitHub.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "Weblate"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.17"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/WeblateOrg/weblate/security/advisories/GHSA-mqph-7h49-hqfm"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-33220"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/WeblateOrg/weblate/pull/18516"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/WeblateOrg/weblate"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/weblate/PYSEC-2026-153.yaml"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-200", "CWE-22" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-16T20:41:29Z",
    "nvd_published_at" : "2026-04-15T19:16:35Z"
  }
}