# CVE-2026-42150: Weblate wlc cross-site scripting in HTML output format

Source: https://junglewise.ai/threats/cve-2026-42150-weblate-wlc-cross-site-scripting-in-print-html  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-08. Updated: 2026-05-14  
License: CC BY 4.0 with a link back

CVE-2026-42150 · Severity: medium · CVSS 5.1 · Published 2026-05-08

wlc is a command-line tool used to interact with the Weblate translation platform. A security flaw in versions prior to 2.0.0 allows malicious data from the Weblate API to be converted into web-ready HTML without proper safety checks. If a user generates an HTML report and views it in a web browser, an attacker could execute malicious scripts, potentially leading to unauthorized actions or data theft within that browser session.

Technologies: [wlc (PyPI)](https://junglewise.ai/threats/technologies/wlc). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2026-42150 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-42150 being exploited in the wild.

**How severe is CVE-2026-42150?** Medium severity, with a CVSS score of 5.1, published 8 May 2026.

**Which products and versions are affected?** wlc (PyPI) < 2.0.0, ECOSYSTEM:introduced=0,fixed=2.0.0.

**Is there a fix for CVE-2026-42150?** Yes. wlc (PyPI): upgrade to 2.0.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-42150 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-42150?** Check whether you run wlc (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- wlc (PyPI): upgrade to 2.0.0 or later

  ```sh
  pip install "wlc>=2.0.0"
  ```


## Technical details

The wlc command-line client (prior to version 2.0.0) contains a stored cross-site scripting (XSS) vulnerability in its HTML output module. The `print_html` function embeds data retrieved from the Weblate REST API directly into HTML tags (such as <th> and <td>) without performing proper character escaping. An attacker with high privileges on a Weblate instance could inject malicious scripts into translation strings or metadata. When a user runs wlc with the `--format=html` flag and opens the resulting file in a browser, the script executes in the context of the local file or the domain hosting the report. This issue is addressed in version 2.0.0 by implementing a `format_html_value` helper to sanitize output.

## Affected products

- WeblateOrg wlc < 2.0.0

## Identifiers

- CVE-2026-42150
- GHSA-gx2m-mcc2-r4p3
- PYSEC-2026-2321

## Timeline

- 2026-04-20: patched: Fix merged into main branch via PR #1327
- 2026-04-21: advisory: Vendor security advisory GHSA-gx2m-mcc2-r4p3 published
- 2026-05-08: disclosed: CVE-2026-42150 published to NVD

## References

- [https://github.com/WeblateOrg/wlc/commit/0f3e58f6d7457b05d48ef40f579a172c4c8b8469](https://github.com/WeblateOrg/wlc/commit/0f3e58f6d7457b05d48ef40f579a172c4c8b8469)
- [https://github.com/WeblateOrg/wlc/pull/1327](https://github.com/WeblateOrg/wlc/pull/1327)
- [https://github.com/WeblateOrg/wlc/releases/tag/2.0.0](https://github.com/WeblateOrg/wlc/releases/tag/2.0.0)
- [https://github.com/WeblateOrg/wlc/security/advisories/GHSA-gx2m-mcc2-r4p3](https://github.com/WeblateOrg/wlc/security/advisories/GHSA-gx2m-mcc2-r4p3)

## Related threats

- [Weblate wlc API token disclosure in project configuration](https://junglewise.ai/threats/cve-2026-62364-weblate-wlc-api-token-disclosure-in-project-configuration)
- [PYSEC-2026-2053 - Weblate wlc path traversal vulnerability: Unsanitized API slugs in download command](https://junglewise.ai/threats/cve-2026-23535-weblate-wlc-path-traversal-vulnerability-unsanitized-api-slugs-in)
- [PYSEC-2026-2052 - Weblate wlc has insecure API key configuration](https://junglewise.ai/threats/cve-2026-22251-weblate-wlc-has-insecure-api-key-configuration)
- [PYSEC-2026-2051 - Weblate command-line client susceptible to SSL verification skip](https://junglewise.ai/threats/cve-2026-22250-weblate-command-line-client-ssl-verification-skip)