CVE-2024-39316: 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) vulner...

Description

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.

Metrics

CVSS 3.1

6.5/10

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

EPSS Probability

0.86%

53.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-1333

Affected Software

Vendor	Product	Versions
Rack	Rack	>= 3.1.0, < 3.1.5

References

Timeline

Published: Jul 2, 2024
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2024-39316?

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.

How severe is CVE-2024-39316?

CVE-2024-39316 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.86% probability of exploitation in the next 30 days.

How do I fix CVE-2024-39316?

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.