What’s Vulnerable › Vulnerabilities
CVE-2024-26146: Possible Denial of Service Vulnerability in Rack Header Parsing
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 2.0% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2024-02-29 · updated 2026-06-17
- Weakness: CWE-1333
Description
Rack is a modular Ruby web server interface. Carefully crafted headers can cause header parsing in Rack to take longer than expected resulting in a possible denial of service issue. Accept and Forwarded headers are impacted. Ruby 3.2 has mitigations for this problem, so Rack applications using Ruby 3.2 or newer are unaffected. This vulnerability is fixed in 2.0.9.4, 2.1.4.4, 2.2.8.1, and 3.0.9.1.
Affected products
- Debian Linux: 10.0
- rack: from 0.4 before 2.0.9.4; from 2.1.0 before 2.1.4.4; from 2.2.0 before 2.2.8.1 — fixed in 2.0.9.4, 2.1.4.4, 2.2.8.1
- Rubygems Rack: from 3.0.0 before 3.0.9.1; from 2.2.0 before 2.2.8.1; from 2.1.0 before 2.1.4.4; before 2.0.9.4; 3.0.0, 3.0.1, 3.0.2, 3.0.3, 3.0.4, 3.0.4.1 (+113) — fixed in 3.0.9.1, 2.2.8.1, 2.1.4.4, 2.0.9.4
How to fix
Upgrade to a fixed version: rack 2.0.9.4, 2.1.4.4, 2.2.8.1; Rubygems Rack 3.0.9.1, 2.2.8.1, 2.1.4.4, 2.0.9.4. Check the vendor advisory for mitigations.
References
- https://discuss.rubyonrails.org/t/possible-denial-of-service-vulnerability-in-rack-header-parsing/84942
- https://github.com/rack/rack/commit/30b8e39a578b25d4bdcc082c1c52c6f164b59716
- https://github.com/rack/rack/commit/6c5d90bdcec0949f7ba06db62fb740dab394b582
- https://github.com/rack/rack/commit/a227cd793778c7c3a827d32808058571569cda6f
- https://github.com/rack/rack/commit/e4c117749ba24a66f8ec5a08eddf68deeb425ccd
- https://github.com/rack/rack/security/advisories/GHSA-54rr-7fvw-6x8f
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/rack/CVE-2024-26146.yml
- https://lists.debian.org/debian-lts-announce/2024/04/msg00022.html
- https://security.netapp.com/advisory/ntap-20240510-0006/
- https://discuss.rubyonrails.org/t/possible-denial-of-service-vulnerability-in-rack-header-parsing/84942
- https://github.com/rack/rack/commit/30b8e39a578b25d4bdcc082c1c52c6f164b59716
- https://github.com/rack/rack/commit/6c5d90bdcec0949f7ba06db62fb740dab394b582
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