CVE-2026-33435: Weblate Remote Code Execution Vulnerability

HIGH
Advisory Identifier: GHSA-558g-h753-6m33
Share
CVSS 8.0
CWE-94 CWE-434 CWE-23
Published
Advisory Summary

CVE-2026-33435 is a HIGH (CVSS 8.0) remote code execution vulnerability (CWE-94: Improper Control of Generation of Code ('Code Injection')) affecting Weblate libraries in the PyPI ecosystem. The issue involves remote code execution during backup restoration. Remediation is available by upgrading affected packages to version 5.17.

CVE-2026-33435 at a Glance

CVE Identifier CVE-2026-33435
GHSA Identifier GHSA-558g-h753-6m33
Severity HIGH
CVSS v3.1 Base Score 8.0
CWE Classification CWE-94: Improper Control of Generation of Code ('Code Injection')
Affected Product Weblate
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 8.0

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

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

How to Fix CVE-2026-33435

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-2026-33435, 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-94: Improper Control of Generation of Code ('Code Injection'), where the product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. 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 project backup didn't filter Git and Mercurial configuration files and this could lead to remote code execution under certain circumstances. ### Patches * https://github.com/WeblateOrg/weblate/pull/18549 ### Workarounds The project backup is only accessible to users who can create projects. Restricting access to this limits scope of the vulnerability. ### References This issue was reported by [ggamno](https://hackerone.com/ggamno) via HackerOne.

CVE-2026-33435 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-558g-h753-6m33
NVD — CVE-2026-33435 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33435
Weblate Source Repository REPOSITORY
https://github.com/WeblateOrg/weblate/pull/18549
Weblate Source Repository REPOSITORY
https://github.com/WeblateOrg/weblate
Weblate Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/weblate/PYSEC-2026-154.yaml

Frequently Asked Questions

What is CVE-2026-33435?
CVE-2026-33435 is a security vulnerability in Weblate involving Remote code execution during backup restoration under CWE-94: Improper Control of Generation of Code ('Code Injection').
Which Weblate versions are affected?
Affected versions include releases prior to 5.17 across affected packages: Weblate.
What version fixes CVE-2026-33435?
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-2026-33435?
CVE-2026-33435 has a CVSS v3.1 base score of 8.0 (HIGH) with vector string CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H.
What CWE is associated with CVE-2026-33435?
CVE-2026-33435 is classified under CWE-94: Improper Control of Generation of Code ('Code Injection') (The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.).
How can I check PyPI dependencies for CVE-2026-33435?
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-558g-h753-6m33",
  "modified" : "2026-06-08T19:54:20Z",
  "published" : "2026-04-16T20:41:38Z",
  "aliases" : [ "CVE-2026-33435" ],
  "summary" : "Weblate: Remote code execution during backup restoration",
  "details" : "### Impact\nThe project backup didn't filter Git and Mercurial configuration files and this could lead to remote code execution under certain circumstances.\n\n### Patches\n* https://github.com/WeblateOrg/weblate/pull/18549\n\n### Workarounds\nThe project backup is only accessible to users who can create projects. Restricting access to this limits scope of the vulnerability.\n\n### References\nThis issue was reported by [ggamno](https://hackerone.com/ggamno) via HackerOne.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H"
  } ],
  "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-558g-h753-6m33"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-33435"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/WeblateOrg/weblate/pull/18549"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/WeblateOrg/weblate"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/weblate/PYSEC-2026-154.yaml"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-23", "CWE-434", "CWE-94" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-16T20:41:38Z",
    "nvd_published_at" : "2026-04-15T19:16:35Z"
  }
}