CVE-2022-24839Network attack vector

Service interruption via unterminated processing instruction

Published Apr 11, 2022 · Updated Apr 23, 2025

Resource exhaustion in the Nokogiri fork of NekoHTML before 1.9.22.noko2 allows remote attackers to interrupt services via malformed HTML. HTMLScanner.scanPI fails to stop when a processing instruction ending in ? or / reaches end of input, repeatedly appending data until heap exhaustion. Any application that parses attacker-controlled HTML through the affected Java library can raise OutOfMemoryError and lose availability; no data access or modification is reported.

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

Resource exhaustion in the Nokogiri fork of NekoHTML before 1.9.22.noko2 allows remote attackers to interrupt services via malformed HTML. HTMLScanner.scanPI fails to stop when a processing instruction ending in ? or / reaches end of input, repeatedly appending data until heap exhaustion. Any application that parses attacker-controlled HTML through the affected Java library can raise OutOfMemoryError and lose availability; no data access or modification is reported.

The record

CVE
CVE-2022-24839
Published
Apr 11, 2022
Updated
Apr 23, 2025
Vendor
NekoHTML Project
Product
NekoHTML
Classifications
CWE-400, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 11, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 23, 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=< 1.9.22.noko2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

NekoHTML Project · NekoHTMLversion=< 1.9.22.noko2

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499.004Application or System Exploitation

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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