CVE-2024-39316

Rack ReDoS Vulnerability in HTTP Accept Headers Parsing

MEDIUM
6.5
CVSS Score
Published: July 2, 2024 at 03:57 PM UTC
Updated: June 17, 2026 at 07:41 AM UTC
1 product affected across 1 vendorRack

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.9%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Rack· Rackrubygems
95%
v < 3.1.53.1.0 ≤ v < 3.1.5
Affected range stops below 3.1.5, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-1333

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