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🛡️ CVE-2023-22795 — actionpack

🟠 CVSS 7.5 — High ✅ No Known Exploit CWE-1333 NVD
7.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

ReDoS based DoS vulnerability in Action Dispatch

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: None.
  • Integrity impact: None.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

CVE-2023-22795 is classified as CWE-1333: Inefficient Regular Expression Complexity. A regular expression backtracks catastrophically on crafted input, consuming CPU out of proportion to input size.

Affected software

CVE-2023-22795 is recorded against 3 packages.

  • actionpack (from 7.0.0 up to 7.0.4.1)
  • debian-linux
  • rails (from 7.0.0 up to 7.0.4.1)

Timeline and source

Published on 18 January 2023 and last revised on 31 March 2025. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

nvd.nist.gov (Advisory)
github.com (Web)
github.com (Web)
github.com (Web)
discuss.rubyonrails.org (Web)
github.com (Package)
github.com (Web)
github.com (Web)
github.com (Web)
rubyonrails.org (Web)

Other advisories for this package

actionpack has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-1333: Inefficient Regular Expression Complexity) in other software:

CVE-2023-22795 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity LOW
CVSS Score 7.5
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE CWE-1333
Public Exploit ✅ No
Source NVD
Published 2023-01-18
Updated 2026-08-20
Modified 2025-03-31

Affected Packages

Software From version Fixed in
actionpack 7.0.0 7.0.4.1
debian-linux — —
rails 7.0.0 7.0.4.1

Similar Threats

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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