CVE-2022-28366: Certain Neko-related HTML parsers allow a denial of service via crafted Processing Instruction (PI) input that

Q: How do I fix CVE-2022-28366?

cyberneko html: upgrade to newer than 1.9.22; htmlunit: upgrade to 2.27; antisamy: upgrade to 1.6.6. Exact commands for each OS are on this page.

Q: Is CVE-2022-28366 being exploited?

CVE-2022-28366 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2022-28366 affect?

CVE-2022-28366 affects cyberneko html, htmlunit, antisamy. Severity is high (CVSS 7.5). Certain Neko-related HTML parsers allow a denial of service via crafted Processing Instruction (PI) input that causes excessive heap memory consumption. In particular, this issue exists in HtmlUnit-Neko through 2.26, and is fixed in 2.27. T

Q: How urgent is CVE-2022-28366?

Priority 52/100. High severity; Remotely exploitable, no login, no user action

This month

HIGH 7.5REMOTEUPGRADEUPGRADEUPGRADE

CVE-2022-28366 is a high-severity flaw (CVSS 7.5) affecting cyberneko html, htmlunit, antisamy. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Certain Neko-related HTML parsers allow a denial of service via crafted Processing Instruction (PI) input that causes excessive heap memory consumption. In particular, this issue exists in HtmlUnit-Neko through 2.26, and is fixed in 2.27. This issue also exists in CyberNeko HTML through 1.9.22 (also affecting OWASP AntiSamy before 1.6.6), but 1.9.22 is the last version of CyberNeko HTML. NOTE: this may be related to CVE-2022-24839.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.2% (top 18%)
CISA exploited list	No
Published	2022-04-21
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: antisamy project · cyberneko html project · htmlunit

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2022-04-21 23:15 UTCPublished CVE record published
2026-06-17 04:38 UTCUpdated Record last modified

cyberneko html project cyberneko html UPGRADE

Affected: <= 1.9.22

Fixed in: newer than 1.9.22

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy cyberneko-html || rpm -q cyberneko-html || cyberneko-html --version

2. UPGRADE to newer than 1.9.22 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade cyberneko-html

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade cyberneko-html

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

htmlunit htmlunit UPGRADE

Affected: < 2.27

Fixed in: 2.27

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy htmlunit || rpm -q htmlunit || htmlunit --version

2. UPGRADE to 2.27 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade htmlunit

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade htmlunit

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

antisamy project antisamy UPGRADE

Affected: < 1.6.6

Fixed in: 1.6.6

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy antisamy || rpm -q antisamy || antisamy --version

2. UPGRADE to 1.6.6 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade antisamy

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade antisamy

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2022-28366?

cyberneko html: upgrade to newer than 1.9.22; htmlunit: upgrade to 2.27; antisamy: upgrade to 1.6.6. Exact commands for each OS are on this page.

Is CVE-2022-28366 being exploited?

CVE-2022-28366 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2022-28366 affect?

CVE-2022-28366 affects cyberneko html, htmlunit, antisamy. Severity is high (CVSS 7.5). Certain Neko-related HTML parsers allow a denial of service via crafted Processing Instruction (PI) input that causes excessive heap memory consumption. In particular, this issue exists in HtmlUnit-Neko through 2.26, and is fixed in 2.27. T

How urgent is CVE-2022-28366?

Priority 52/100. High severity; Remotely exploitable, no login, no user action

References

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