TI-2024-26272 Aliases CVE-2024-39316 GHSA-cj83-2ww7-mvq7

Rack ReDoS Vulnerability in HTTP Accept Headers Parsing

LOW 30CWE-1333Published 2024-07-02 · Updated 2024-08-02

Key facts

Attack vector: Network
Privileges required: Low
User interaction: None
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-1333.

Summary

Rack is a modular Ruby web server interface. Starting in version 3.1.0 and prior to version 3.1.5, Regular Expression Denial of Service (ReDoS) vulnerability exists in the `Rack::Request::Helpers` module when parsing HTTP Accept headers. This vulnerability can be exploited by an attacker sending specially crafted `Accept-Encoding` or `Accept-Language` headers, causing the server to spend excessive time processing the request and leading to a Denial of Service (DoS). The fix for CVE-2024-26146 was not applied to the main branch and thus while the issue was fixed for the Rack v3.0 release series, it was not fixed in the v3.1 release series until v3.1.5. Users of versions on the 3.1 branch should upgrade to version 3.1.5 to receive the fix.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00856 58th percentileScored 2026-11-07

Fix Fixed rack (rack): 3.1.5rack (RubyGems): 3.1.5

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
rack	rack	3.1.0 to before 3.1.5	3.1.5	Patch available	CNA
—	rack (RubyGems)	3.1.0 to before 3.1.5	3.1.5	Patch available	GHSA-cj83-2ww7-mvq7

rack Vendorrack Affected 3.1.0 to before 3.1.5 Fixed in 3.1.5 Patch available CNA
rack (RubyGems) Vendor— Affected 3.1.0 to before 3.1.5 Fixed in 3.1.5 Patch available GHSA-cj83-2ww7-mvq7

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:rack:rack::::::ruby::*	3.1.0 to before 3.1.5	Vulnerable	rack

cpe:2.3:a:rack:rack:*:*:*:*:*:ruby:*:* Versions 3.1.0 to before 3.1.5 Vulnerable ·rack

Remediation

Fix · CNA rack (rack) Fixed in 3.1.5
Fix · GHSA-cj83-2ww7-mvq7 rack (RubyGems) Fixed in 3.1.5 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2024-39316
2026-10-03 Alias added: GHSA-cj83-2ww7-mvq7

References

Patch 1

https://github.com/rack/rack/commit/412c980450ca729ee37f90a2661f166a9665e058

Advisory 2

Other 4

TI-2024-16580 Rack ReDos in content type parsing (2nd degree polynomial) CVSS 3.1HIGH 7.5
TI-2024-17236 Possible Denial of Service Vulnerability in Rack Header Parsing CVSS 3.1HIGH 7.5
TI-2024-17231 Possible DoS Vulnerability with Range Header in Rack CVSS 3.1HIGH 7.5
TI-2023-12254 Uncontrolled resource consumption in https://github.com/rack/rack CVSS 3.1HIGH 7.5
TI-2025-38165 Rack's multipart parser buffers unbounded per-part headers, enabling DoS (memory exhaustion) CVSS 3.1HIGH 7.5
TI-2025-38163 Rack's unbounded multipart preamble buffering enables DoS (memory exhaustion) CVSS 3.1HIGH 7.5

See all 36 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences