# CVE-2026-42150: wlc: print_html outputs API data without HTML escaping, enabling stored XSS

> The wlc CLI tool fails to escape HTML in its output, allowing attackers to inject scripts that execute when the output is viewed in a browser.

- **Severity:** Medium 5.1 (`CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:C/C:L/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 8 May 2026
- **Updated:** 8 May 2026
- **Also known as:** DEBIAN-CVE-2026-42150, GHSA-gx2m-mcc2-r4p3, PYSEC-2026-2321, UBUNTU-CVE-2026-42150

## What is CVE-2026-42150?

CVE-2026-42150 is a medium-severity cross-site scripting vulnerability in WeblateOrg wlc, published on 8 May 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

### Official description

wlc is a Weblate command-line client using Weblate's REST API. Prior to version 2.0.0, the HTML output format in wlc embeds API response data into HTML without escaping, allowing cross-site scripting when the output is rendered in a browser. This issue has been patched in version 2.0.0.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-42150?

3 open source packages ship an affected version, including wlc. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `wlc` | PyPI | All versions | 2.0.0 |
| `wlc` | PyPI | All versions | 2.0.0 |
| `wlc` | PyPI | All versions | 2.0.0 |

Products: Weblate Wlc.

## How do I fix CVE-2026-42150?

Upgrade wlc to 2.0.0 or later.

## Is CVE-2026-42150 being exploited?

There is no known exploitation of CVE-2026-42150 in the wild and no public exploit code.

## Other vulnerabilities in WeblateOrg wlc

- [CVE-2026-23535](https://insights.sbomify.com/CVE-2026-23535/): wlc Path traversal: Unsanitized API slugs in download command (high 8.1)
- [CVE-2026-22251](https://insights.sbomify.com/CVE-2026-22251/): wlc may leak API keys due to an insecure API key configuration (medium 5.3)
- [CVE-2026-22250](https://insights.sbomify.com/CVE-2026-22250/): wlc can skip SSL verification (low 2.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-42150 and fix it if it is affected.

What it is: CVE-2026-42150 is a medium-severity cross-site scripting vulnerability in WeblateOrg wlc, published on 8 May 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-42150 in the wild and no public exploit code.

Affected packages and fixed versions:
- wlc (PyPI): affected all versions; fixed in 2.0.0
- wlc (PyPI): affected all versions; fixed in 2.0.0
- wlc (PyPI): affected all versions; fixed in 2.0.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-42150/ (Markdown: https://insights.sbomify.com/CVE-2026-42150/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42150
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42150
- OSV: https://osv.dev/vulnerability/CVE-2026-42150

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-42150/
Summaries are generated and may contain mistakes; the official description above is the record.