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Fencer Vulns
high 7.5

CVE-2021-22902 json

Denial of Service in Action Dispatch

published 2021-05-05 5 y ago modified 2026-06-17 4 mo ago also GHSA-g8ww-46x2-2p65 , EUVD-2021-1076

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.9%
EPSS 2.9% chance of exploitation in 30 days, percentile 86%
public exploits
0
none known

Summary

The actionpack ruby gem (a framework for handling and responding to web requests in Rails) before 6.0.3.7, 6.1.3.2 suffers from a possible denial of service vulnerability in the Mime type parser of Action Dispatch. Carefully crafted Accept headers can cause the mime type parser in Action Dispatch to do catastrophic backtracking in the regular expression engine.

Patch / fix

  • rubygems actionpack 6.0.3.7, 6.1.3.2
  • rubyonrails rails 6.0.3.7, 6.1.0.2
  • rails Debian 14, Debian 13, Debian 12 2:6.0.3.7+dfsg-1

debian advisories DEBIAN-CVE-2021-22902

  • foreman satellite capsule 6.10, satellite 6.10 2.5.2.17-2.el7sat
  • candlepin satellite 6.10 4.0.9-1.el7sat
  • satellite satellite capsule 6.10, satellite 6.10 6.10.0-3.el7sat
  • python-ecdsa satellite capsule 6.10, satellite 6.10 0.13.3-2.el7pc
  • python-pyyaml satellite capsule 6.10, satellite 6.10 5.4.1-1.el7pc
  • python3-ecdsa satellite capsule 6.10, satellite 6.10 0.13.3-2.el7pc
  • python-aiohttp satellite capsule 6.10, satellite 6.10 3.7.4-1.el7pc
  • python-urllib3 satellite capsule 6.10, satellite 6.10 1.26.5-1.el7pc

red hat advisories RHSA-2021:4702

  • rubygem-actionpack-6.0 openSUSE Tumbleweed 6.0.4.4-1.1

opensuse advisories openSUSE-SU-2024:11821-1

  • gitlab Arch Linux 14.0.0-1
  • gitlab-gitaly Arch Linux 14.1.0-1

arch linux advisories AVG-2090AVG-2223

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-22902 updated cvss 7.5

rails: Possible Denial of Service vulnerability in Action Dispatch

  • Red Hat Satellite 6.10 tfm-rubygem-rails 6.0.3.7-1.el7sat
    fixed: vendor fix RHSA-2021:4702
  • Red Hat CloudForms Management Engine 5 cfme-gemset Red Hat Satellite 6 tfm-ror52-rubygem-actionpack Red Hat Satellite 6.10 tfm 7.0-1.el7sat, gofer 2.12.5-7.el7sat, katello 4.1.1-2.el7sat, libsolv 0.7.20-1.el7pc, receptor 0.6.4-2.el7ar, libcomps 0.1.15-1.el7pc, +584 more Red Hat Satellite Capsule 6.10 tfm 7.0-1.el7sat, katello 4.1.1-2.el7sat, libsolv 0.7.20-1.el7pc, libcomps 0.1.15-1.el7pc, python-rq 1.8.1-1.el7pc, python-idna 2.10-1.el7pc, +369 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.87% chance of exploitation in the next 30 days, higher than 86% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • discuss.rubyonrails.org https://discuss.rubyonrails.org/t/cve-2021-22902-possible-denial-of-service-vulnerability-in-action-dispatch/77866 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
rubygems actionpack
>=6.0.0, <6.0.3.7
>=6.1.0, <6.1.3.2
6.0.3.7
6.1.3.2

Affected products

  • n/a https://github.com/rails/rails

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.