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ReDoS based DoS vulnerability in Action Dispatch

Low severity GitHub Reviewed Published Jan 18, 2023 to the GitHub Advisory Database • Updated May 16, 2023

Package

bundler actionpack (RubyGems)

Affected versions

>= 7.0.0, < 7.0.4.1
< 6.1.7.1

Patched versions

7.0.4.1
6.1.7.1

Description

There is a possible regular expression based DoS vulnerability in Action Dispatch related to the If-None-Match header. This vulnerability has been assigned the CVE identifier CVE-2023-22795.

Versions Affected: All Not affected: None Fixed Versions: 5.2.8.15 (Rails LTS), 6.1.7.1, 7.0.4.1

Impact

A specially crafted HTTP If-None-Match header can cause the regular expression engine to enter a state of catastrophic backtracking, when on a version of Ruby below 3.2.0. This can cause the process to use large amounts of CPU and memory, leading to a possible DoS vulnerability All users running an affected release should either upgrade or use one of the workarounds immediately.
Releases

The FIXED releases are available at the normal locations.
Workarounds

We recommend that all users upgrade to one of the FIXED versions. In the meantime, users can mitigate this vulnerability by using a load balancer or other device to filter out malicious If-None-Match headers before they reach the application.

Users on Ruby 3.2.0 or greater are not affected by this vulnerability.
Patches

To aid users who aren’t able to upgrade immediately we have provided patches for the two supported release series. They are in git-am format and consist of a single changeset.

6-1-Avoid-regex-backtracking-on-If-None-Match-header.patch - Patch for 6.1 series
7-0-Avoid-regex-backtracking-on-If-None-Match-header.patch - Patch for 7.0 series

Please note that only the 7.0.Z and 6.1.Z series are supported at present, and 6.0.Z for severe vulnerabilities. Users of earlier unsupported releases are advised to upgrade as soon as possible as we cannot guarantee the continued availability of security fixes for unsupported releases.

References

Published to the GitHub Advisory Database Jan 18, 2023
Reviewed Jan 18, 2023
Published by the National Vulnerability Database Feb 9, 2023
Last updated May 16, 2023

Severity

Low

EPSS score

3.705%
(92nd percentile)

Weaknesses

CVE ID

CVE-2023-22795

GHSA ID

GHSA-8xww-x3g3-6jcv

Source code

Credits

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