How severe is CVE-2026-42150?

CVE-2026-42150 has a CVSS score of 5.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2026-42150?

CVE-2026-42150 affects the following packages: wlc (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2026-42150?

Update wlc to 2.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-42150 is resolved across your whole dependency graph.

How do I detect CVE-2026-42150 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for wlc, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-42150 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2026-42150 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-42150 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-42150?

CVE-2026-42150 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 7th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-42150?

CVE-2026-42150 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-42150 published, and has it been updated?

CVE-2026-42150 was published on May 8, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍

🐍 PyPI

Not in CISA KEV

MEDIUM severity

CVE-2026-42150 — wlc

MEDIUMFix: WeblateOrg/wlc@0f3e58f

CVE-2026-42150 is a medium-severity (CVSS 5.1) Cross-site Scripting (XSS) vulnerability in wlc. A fix is available for wlc — see the affected versions and patch details below.

wlc: print_html outputs API data without HTML escaping, enabling stored XSS

Also known asGHSA-gx2m-mcc2-r4p3PYSEC-2026-2321

Published

May 8, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-42150.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs7th percentile — riskier than 7% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

🐍wlc

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Impact

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.

Patches

https://github.com/WeblateOrg/wlc/pull/1327

Workarounds

The only vulnerable code path is HTML output which is opt-in.

References

Weblate thanks @fg0x0 for reporting this on GitHub.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`wlc`	all versions	2.0.0`pip install --upgrade 'wlc==2.0.0'`

Affected Products

1 product · 1 configurations

Application

wlcweblate

< 2.0.0

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for wlc, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update wlc to 2.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-42150 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

### Impact 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. ### Patches * https://github.com/WeblateOrg/wlc/pull/1327 ### Workarounds The only vulnerable code path is HTML output which is opt-in. ### References Weblate thanks @fg0x0 for reporting this on GitHub.