CVE-2024-35221Public exploitNetwork attack vector

Service interruption via YAML alias expansion

Published May 29, 2024 · Updated Aug 2, 2024

Denial of service in RubyGems.org before 2024-04-12 allows remote authenticated users to interrupt the hosted service by publishing crafted gems. The Pusher path parses a gem metadata manifest with Gem::Specification.from_yaml, whose SafeYAML.load permits recursive YAML aliases that expand into a YAML bomb. A valid publishing credential and repeated uploads are required to occupy every worker, after which the Rails application stops responding.

CVSS severity4.3
Medium
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in RubyGems.org before 2024-04-12 allows remote authenticated users to interrupt the hosted service by publishing crafted gems. The Pusher path parses a gem metadata manifest with Gem::Specification.from_yaml, whose SafeYAML.load permits recursive YAML aliases that expand into a YAML bomb. A valid publishing credential and repeated uploads are required to occupy every worker, after which the Rails application stops responding.

The record

CVE
CVE-2024-35221
Published
May 29, 2024
Updated
Aug 2, 2024
Vendor
RubyGems
Product
RubyGems.org
Classifications
CWE-400, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 29, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2024-04-12

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

RubyGems · RubyGems.orgversion=< 2024-04-12

Published CVSS scores

4.3GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499.004Application or System Exploitation Flood

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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