CVE-2022-28366Network attack vector

Heap exhaustion via processing-instruction parsing loop

Published Apr 21, 2022 · Updated Aug 3, 2024

Uncontrolled resource consumption in HtmlUnit-Neko through 2.26 allows remote attackers to exhaust Java heap memory via crafted PI input. The related upstream patch makes HTMLScanner.scanPI recognize end-of-file after a terminal question mark or slash; otherwise, the loop repeatedly appends the delimiter to fStringBuffer. The flaw also affects CyberNeko HTML through 1.9.22 and OWASP AntiSamy before 1.6.6 when attacker-supplied HTML reaches the parser, causing the hosting service to hang or crash.

CVSS severity7.5
High
EPSS probability2.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled resource consumption in HtmlUnit-Neko through 2.26 allows remote attackers to exhaust Java heap memory via crafted PI input. The related upstream patch makes HTMLScanner.scanPI recognize end-of-file after a terminal question mark or slash; otherwise, the loop repeatedly appends the delimiter to fStringBuffer. The flaw also affects CyberNeko HTML through 1.9.22 and OWASP AntiSamy before 1.6.6 when attacker-supplied HTML reaches the parser, causing the hosting service to hang or crash.

The record

CVE
CVE-2022-28366
Published
Apr 21, 2022
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 21, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5GitHub Advisory DatabaseCVSS: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 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

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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