CVE-2022-30122Network attack vector

Service interruption via malformed multipart filename regex

Published Dec 5, 2022 · Updated Nov 19, 2024

Regular-expression denial of service in Rack allows remote attackers to interrupt service by sending crafted multipart POST requests. Rack::Multipart::Parser uses permissive BROKEN_QUOTED and BROKEN_UNQUOTED regular expressions to recover malformed Content-Disposition filenames, allowing ambiguous quotes to drive excessive backtracking. Any remotely reachable application that parses multipart posts through Rack, including through Request#POST or Request#params, exposes the CPU-intensive path and can become unresponsive.

CVSS severity7.5
High
EPSS probability2.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Regular-expression denial of service in Rack allows remote attackers to interrupt service by sending crafted multipart POST requests. Rack::Multipart::Parser uses permissive BROKEN_QUOTED and BROKEN_UNQUOTED regular expressions to recover malformed Content-Disposition filenames, allowing ambiguous quotes to drive excessive backtracking. Any remotely reachable application that parses multipart posts through Rack, including through Request#POST or Request#params, exposes the CPU-intensive path and can become unresponsive.

The record

CVE
CVE-2022-30122
Published
Dec 5, 2022
Updated
Nov 19, 2024
Vendor
Rack
Product
Rack
Classifications
CWE-1333, CWE-400, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 5, 2022CVE publishedPublication date reported by the CVE source.
  2. Nov 19, 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=2.0.9.1, 2.1.4.1, 2.2.3.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Rack · Rackversion=2.0.9.1, 2.1.4.1, 2.2.3.1

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 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
CWE-400Uncontrolled Resource Consumption
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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