CVE-2021-22902 Denial of Service in Action Dispatch

What is CVE-2021-22902?

CVE-2021-22902 is a high-severity denial of service vulnerability in Rubyonrails Rails, published on 11 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

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.

Weakness: CWE-400

Which versions are affected by CVE-2021-22902?

4 open source packages ship an affected version, including actionpack. It affects 1 product.

Products include Rubyonrails Rails.

How do I fix CVE-2021-22902?

Upgrade actionpack to a fixed version for your release line: 6.0.3.7 or 6.1.3.2.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2021-22902 being exploited?

There is no known exploitation of CVE-2021-22902 in the wild and no public exploit code.

Other vulnerabilities in Rubyonrails Rails

• CVE-2013-0277 Active Record contains deserialization of arbitrary YAML Critical 10.0
• CVE-2017-17916 SQL injection in n/a High 8.1
• CVE-2017-17917 SQL injection in n/a High 8.1
• CVE-2026-33195 Rails Active Storage has possible Path Traversal in DiskService High 8.0
• CVE-2024-26142 Rails possible ReDoS vulnerability in Accept header parsing in Action Dispatch High 7.5

All Rubyonrails Rails vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2021-22902, GHSA-g8ww-46x2-2p65, UBUNTU-CVE-2021-22902.