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Vulnerabilities

Vulnerability · CVE-2021-22904

The actionpack ruby gem before 6.1.3.2, 6.0.3.7, 5.2.4.6, 5.2.6 suffers from a possible denial of service vulnerability in the Token Authentication logic in Action Con…

Published Jun 11, 2021 · catalog updated Jun 17, 2026 · the affected product

Last checked Nov 8, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2021-22904. EPSS is 4.87%. Act only if a listed version of the affected product is installed.

Gaps on this record

  • No plain product name is stored. The page cannot tell you which product to check.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
4.87%
Remediation
Version ranges on file
Affected products
cpe rubyonrails/rails

The actionpack ruby gem before 6.1.3.2, 6.0.3.7, 5.2.4.6, 5.2.6 suffers from a possible denial of service vulnerability in the Token Authentication logic in Action Controller due to a too permissive regular expression. Impacted code uses or for request authentication.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe rubyonrails/rails< 5.2.4.6
  • cpe rubyonrails/rails< 5.2.6
  • cpe rubyonrails/rails< 6.0.3.7
  • cpe rubyonrails/rails< 6.1.3.2

How to fix CVE-2021-22904

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2021-22904. EPSS is 4.87%. Act only if a listed version of the affected product is installed.

Which versions are affected?

Compare what you have installed with < 5.2.4.6, < 5.2.6, < 6.0.3.7, < 6.1.3.2. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-400: Uncontrolled Resource Consumption. EPSS 4.87%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Ruby on Rails security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 11, 2021 · Monitored products — high

    Detected

    The actionpack ruby gem before 6.1.3.2, 6.0.3.7, 5.2.4.6, 5.2.6 suffers from a possible denial of service vulnerability in the Token Authentication logic in Action Controller due to a too permissive regular expression. Impacted code uses or for request authentication.

  2. Jun 17, 2026 · Monitored products — high

    Updated

    The actionpack ruby gem before 6.1.3.2, 6.0.3.7, 5.2.4.6, 5.2.6 suffers from a possible denial of service vulnerability in the Token Authentication logic in Action Controller due to a too permissive regular expression. Impacted code uses or for request authentication.

Sources

  • CVE.orgVulnerability recordCVE-2021-22904

    Official CVE identifier

    cve.org
  • Monitored products — highVendor advisoryCVE-2021-22904

    The actionpack ruby gem before 6.1.3.2, 6.0.3.7, 5.2.4.6, 5.2.6 suffers from a possible denial of service vulnerability in the Token Authentication logic in Action Controller due to a too permissive regular expression. Impacted code uses or for request authentication.

    nvd.nist.gov

References

Freshness

Last verified in this catalog Nov 8, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgNov 8, 2026
  • Monitored products — highNov 8, 2026