What’s Vulnerable › Vulnerabilities

CVE-2024-35221: Denial of service when publishing a package on rubygems.org

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2024-05-29 · updated 2026-06-17
• Weakness: CWE-400

Description

Rubygems.org is the Ruby community's gem hosting service. A Gem publisher can cause a Remote DoS when publishing a Gem. This is due to how Ruby reads the Manifest of Gem files when using Gem::Specification.from_yaml. from_yaml makes use of SafeYAML.load which allows YAML aliases inside the YAML-based metadata of a gem. YAML aliases allow for Denial of Service attacks with so-called `YAML-bombs` (comparable to Billion laughs attacks). This was patched. There is is no action required by users. This issue is also tracked as GHSL-2024-001 and was discovered by the GitHub security lab.

Affected products

• rubygems.org: before 2024-04-12

References

• https://en.wikipedia.org/wiki/Billion_laughs_attack
• https://github.com/ruby/ruby/blob/7cf74a2ff28b1b4c26e367d0d67521f7e1fed239/lib/rubygems/safe_yaml.rb#L28
• https://github.com/rubygems/rubygems.org/security/advisories/GHSA-4vc5-whwr-7hh2
• https://en.wikipedia.org/wiki/Billion_laughs_attack
• https://github.com/ruby/ruby/blob/7cf74a2ff28b1b4c26e367d0d67521f7e1fed239/lib/rubygems/safe_yaml.rb#L28
• https://github.com/rubygems/rubygems.org/security/advisories/GHSA-4vc5-whwr-7hh2

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