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Vulnerabilities

Vulnerability · CVE-2023-22795

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.

Published Feb 9, 2023 · catalog updated Oct 24, 2026 · A regular expression based

Last checked Oct 25, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2023-22795. EPSS is 2.28%. Act only if a listed version of A regular expression based is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (A regular expression based).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
2.28%
Remediation
Version ranges on file
Affected products
cpe debian/debian linux · cpe rubyonrails/rails

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe debian/debian linux11.0
  • cpe rubyonrails/rails< 6.1.7.1
  • cpe rubyonrails/rails< 7.0.4.1

How to fix CVE-2023-22795

  • Upgrade

    CVE-2023-22795 lists a fix boundary at 6.1.7.1. Compare the installed build with that boundary before you change production.

  • Version check

    Affected < 6.1.7.1

  • Advisory

    Open the cve_org record and follow its fix.

  • Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2023-22795. EPSS is 2.28%. Act only if a listed version of A regular expression based is installed.

Which versions are affected?

Compare what you have installed with debian/debian linux 11.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-1333: Inefficient Regular Expression Complexity; CWE-400: Uncontrolled Resource Consumption. EPSS 2.28%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Feb 9, 2023 · NIST NVD

    Detected

    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 vulnerabilit

  2. Oct 24, 2026 · NIST NVD

    Updated

    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 vulnerabilit

Sources

  • CVE.orgVulnerability recordCVE-2023-22795

    Official CVE identifier

    cve.org
  • NIST NVDVulnerability recordCVE-2023-22795

    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 Rub

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 25, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgOct 24, 2026
  • NIST NVDOct 24, 2026