CVE-2023-22795Network attack vector

Service interruption via If-None-Match regex backtracking

Published Feb 9, 2023 · Updated Aug 2, 2024

ReDoS in Ruby on Rails Action Dispatch before 6.1.7.1 or 7.0.0 through 7.0.4 allows remote attackers to interrupt service. The if_none_match_etags method in actionpack/lib/action_dispatch/http/cache.rb splits the untrusted header with /\s*,\s*/, permitting catastrophic regex backtracking. Exploitation requires no authentication or user interaction, but Ruby before 3.2.0 must process the request; CPU and memory exhaustion interrupts the serving process.

CVSS severity7.5
High
EPSS probability2.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

ReDoS in Ruby on Rails Action Dispatch before 6.1.7.1 or 7.0.0 through 7.0.4 allows remote attackers to interrupt service. The if_none_match_etags method in actionpack/lib/action_dispatch/http/cache.rb splits the untrusted header with /\s*,\s*/, permitting catastrophic regex backtracking. Exploitation requires no authentication or user interaction, but Ruby before 3.2.0 must process the request; CPU and memory exhaustion interrupts the serving process.

The record

CVE
CVE-2023-22795
Published
Feb 9, 2023
Updated
Aug 2, 2024
Vendor
Ruby on Rails
Product
Ruby on Rails
Classifications
CWE-1333, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 9, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.1.7.1, 7.0.4.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Ruby on Rails · Ruby on Railsversion=6.1.7.1, 7.0.4.1

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1333Inefficient Regular Expression Complexity
T1499.003Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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