There is a denial of service vulnerability in the multipart parsing component of Rack. This vulnerability has been assigned the CVE identifier CVE-2022-44572.

Versions Affected: >= 2.0.0 Not affected: None. Fixed Versions: 2.0.9.2, 2.1.4.2, 2.2.6.1, 3.0.0.1
Impact

Carefully crafted input can cause RFC2183 multipart boundary parsing in Rack to take an unexpected amount of time, possibly resulting in a denial of service attack vector. Any applications that parse multipart posts using Rack (virtually all Rails applications) are impacted.
Releases

The fixed releases are available at the normal locations.
Workarounds

There are no feasible workarounds for this issue.
Patches

To aid users who aren’t able to upgrade immediately we have provided patches for the two supported release series. They are in git-am format and consist of a single changeset.

2-0-Forbid-control-characters-in-attributes.patch - Patch for 2.0 series
2-1-Forbid-control-characters-in-attributes.patch - Patch for 2.1 series
2-2-Forbid-control-characters-in-attributes.patch - Patch for 2.2 series
3-0-Forbid-control-characters-in-attributes.patch - Patch for 3.0 series

References

• https://github.com/rack/rack/releases/tag/v3.0.4.1
• https://github.com/rubysec/ruby-advisory-db/blob/master/gems/rack/CVE-2022-44572.yml
• https://nvd.nist.gov/vuln/detail/CVE-2022-44572
• https://hackerone.com/reports/1639882
• https://www.debian.org/security/2023/dsa-5530