CVE-2022-35923Public exploitNetwork attack vector

Service interruption via lowercase and uppercase regex backtracking

Published Aug 2, 2022 · Updated Apr 22, 2025

Regular expression denial of service in imbrn v8n before 1.5.1 allows remote attackers to interrupt applications via crafted strings. The lowercase() and uppercase() rules apply nested quantified groups such as ^([a-z]+\s*)+$, causing catastrophic backtracking on a long near-match. Exposure requires a consuming application to pass attacker-controlled text into either rule; processing can stall JavaScript execution and interrupt dependent service.

CVSS severity7.5
High
EPSS probability1.63%
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 imbrn v8n before 1.5.1 allows remote attackers to interrupt applications via crafted strings. The lowercase() and uppercase() rules apply nested quantified groups such as ^([a-z]+\s*)+$, causing catastrophic backtracking on a long near-match. Exposure requires a consuming application to pass attacker-controlled text into either rule; processing can stall JavaScript execution and interrupt dependent service.

The record

CVE
CVE-2022-35923
Published
Aug 2, 2022
Updated
Apr 22, 2025
Vendor
imbrn
Product
v8n
Classifications
CWE-400, CWE-1333, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 2, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 22, 2025Record 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=< 1.5.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

imbrn · v8nversion=< 1.5.1

Published CVSS scores

7.5GitHub, Inc.CVSS: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 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 exploitPublished

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
CWE-1333Inefficient Regular Expression Complexity
T1499.004Application or System Exploitation

Public exploit references

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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