Summary
Rails has possible ReDoS vulnerability in Accept header parsing in Action Dispatch
Possible ReDoS vulnerability in Accept header parsing in Action Dispatch
There is a possible ReDoS vulnerability in the Accept header parsing routines
of Action Dispatch. This vulnerability has been assigned the CVE identifier
CVE-2024-26142.
Versions Affected: >= 7.1.0, < 7.1.3.1
Not affected: < 7.1.0
Fixed Versions: 7.1.3.1
Impact
Carefully crafted Accept headers can cause Accept header parsing in Action
Dispatch to take an unexpected amount of time, possibly resulting in a DoS
vulnerability. All users running an affected release should either upgrade or
use one of the workarounds immediately.
Ruby 3.2 has mitigations for this problem, so Rails applications using Ruby
3.2 or newer are unaffected.
Releases
The fixed releases are available at the normal locations.
Workarounds
There are no feasible workarounds for this issue.
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.
- 7-1-accept-redox.patch - Patch for 7.1 series
Credits
Thanks svalkanov for the report and patch!
Impact
A regular expression with worst-case exponential or polynomial matching time is applied to untrusted input, causing excessive CPU use. Typical impact: denial of service when input is crafted to trigger backtracking.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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See it in your environmentNew to Kodem? Get a demo →Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2024-26142? CVE-2024-26142 is a low-severity inefficient regular expression (ReDoS) vulnerability in actionpack (rubygems), affecting versions >= 7.1.0, < 7.1.3.1. It is fixed in 7.1.3.1. A regular expression with worst-case exponential or polynomial matching time is applied to untrusted input, causing excessive CPU use.
- Which versions of actionpack are affected by CVE-2024-26142? actionpack (rubygems) versions >= 7.1.0, < 7.1.3.1 is affected.
- Is there a fix for CVE-2024-26142? Yes. CVE-2024-26142 is fixed in 7.1.3.1. Upgrade to this version or later.
- Is CVE-2024-26142 exploitable, and should I be worried? Whether CVE-2024-26142 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2024-26142 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2024-26142? Upgrade
actionpackto 7.1.3.1 or later.