CVE-2023-22795: High severity rubyonrails Rails vulnerability
A regular expression based DoS vulnerability in Action Dispatch <6.1.7.1 and <7.0.4.1 related to the If-None-Match header. 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.
Other sources
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 Denial of Service vulnerability.
— Red Hat
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.
— GitHub
Affected Software
Remediation
Event History
Frequently Asked Questions
What is CVE-2023-22795?
CVE-2023-22795 is a regular expression based Denial of Service (DoS) vulnerability in Action Dispatch.
Which versions of Action Dispatch are affected by CVE-2023-22795?
Action Dispatch versions <6.1.7.1 and <7.0.4.1 are affected by CVE-2023-22795.
What is the vulnerability in CVE-2023-22795 related to?
CVE-2023-22795 is related to the If-None-Match header.
How can CVE-2023-22795 be exploited?
CVE-2023-22795 can be exploited by sending a specially crafted HTTP If-None-Match header.
How can I mitigate CVE-2023-22795?
To mitigate CVE-2023-22795, upgrade to a version of Action Dispatch that is not vulnerable (>=6.1.7.1 or >=7.0.4.1).