CVE-2021-22904

Name: CVE-2021-22904
Creator: NVD / NIST
Published: 2021-06-11T16:15:11.517+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 4.81%

Last modified Jun 17, 2026

CVE-2021-22904 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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 `authenticate_or_request_with_http_token` or `authenticate_with_http_token` for request authentication.. EPSS estimates a 4.81% chance of exploitation in the next 30 days.

Description

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 `authenticate_or_request_with_http_token` or `authenticate_with_http_token` for request authentication.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

4.81%

90.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-400

Affected Software

Vendor	Product	Versions
Rubyonrails	Rails	< 5.2.4.6
Rubyonrails	Rails	>= 5.2.5, < 5.2.6
Rubyonrails	Rails	>= 6.0.0, < 6.0.3.7
Rubyonrails	Rails	>= 6.1.0, < 6.1.3.2

References

https://discuss.rubyonrails.org/t/cve-2021-22904-possible-dos-vulnerability-in-action-controller-token-authentication/77869Exploit, Mitigation, Patch, Vendor Advisory
https://hackerone.com/reports/1101125Permissions Required, Third Party Advisory
https://security.netapp.com/advisory/ntap-20210805-0009/Third Party Advisory
https://discuss.rubyonrails.org/t/cve-2021-22904-possible-dos-vulnerability-in-action-controller-token-authentication/77869Exploit, Mitigation, Patch, Vendor Advisory
https://hackerone.com/reports/1101125Permissions Required, Third Party Advisory
https://security.netapp.com/advisory/ntap-20210805-0009/Third Party Advisory

Timeline

Published: Jun 11, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-22904?

How severe is CVE-2021-22904?

CVE-2021-22904 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 4.81% probability of exploitation in the next 30 days.

How do I fix CVE-2021-22904?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-22904?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST