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Rack vulnerable to ReDoS in content type parsing (2nd degree polynomial)

Moderate severity GitHub Reviewed Published Feb 28, 2024 in rack/rack • Updated Jun 10, 2024

Package

bundler rack (RubyGems)

Affected versions

>= 3.0.0, < 3.0.9.1
>= 0.4, < 2.2.8.1

Patched versions

3.0.9.1
2.2.8.1

Description

Summary

module Rack
  class MediaType
    SPLIT_PATTERN = %r{\s*[;,]\s*}

The above regexp is subject to ReDos. 50K blank characters as a prefix to the header will take over 10s to split.

PoC

A simple HTTP request with lots of blank characters in the content-type header:

request["Content-Type"] = (" " * 50_000) + "a,"

Impact

It's a very easy to craft ReDoS. Like all ReDoS the impact is debatable.

References

@tenderlove tenderlove published to rack/rack Feb 28, 2024
Published to the GitHub Advisory Database Feb 28, 2024
Reviewed Feb 28, 2024
Published by the National Vulnerability Database Feb 29, 2024
Last updated Jun 10, 2024

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS score

0.044%
(12th percentile)

Weaknesses

CVE ID

CVE-2024-25126

GHSA ID

GHSA-22f2-v57c-j9cx

Source code

Credits

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