Impact

The REXML gem before 3.3.6 has a DoS vulnerability when it parses an XML that has many deep elements that have same local name attributes.

If you need to parse untrusted XMLs with tree parser API like REXML::Document.new, you may be impacted to this vulnerability. If you use other parser APIs such as stream parser API and SAX2 parser API, this vulnerability is not affected.

Patches

The REXML gem 3.3.6 or later include the patch to fix the vulnerability.

Workarounds

Don't parse untrusted XMLs with tree parser API.

References

• https://www.ruby-lang.org/en/news/2024/08/22/dos-rexml-cve-2024-43398/ : An announce on www.ruby-lang.org

References

• GHSA-vmwr-mc7x-5vc3
• https://nvd.nist.gov/vuln/detail/CVE-2024-43398
• ruby/rexml@7cb5eae
• https://github.com/ruby/rexml/releases/tag/v3.3.6
• https://github.com/rubysec/ruby-advisory-db/blob/master/gems/rexml/CVE-2024-43398.yml
• https://www.ruby-lang.org/en/news/2024/08/22/dos-rexml-cve-2024-43398