CVE-2025-6496Public exploit

Parser crash via null-derived pointer read

Published Jun 23, 2025 · Updated Jun 23, 2025

NULL pointer dereference in HTML Tidy 5.8.0 allows local users to crash the parser with a crafted HTML document. While parsing the supplied input, InsertNodeAsParent performs a read through a null-derived address at src/parser.c line 143. Exploitation requires local low-privileged access and interrupts the invoking process, with no reported data disclosure or modification.

CVSS severity3.3
Low
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in HTML Tidy 5.8.0 allows local users to crash the parser with a crafted HTML document. While parsing the supplied input, InsertNodeAsParent performs a read through a null-derived address at src/parser.c line 143. Exploitation requires local low-privileged access and interrupts the invoking process, with no reported data disclosure or modification.

The record

CVE
CVE-2025-6496
Published
Jun 23, 2025
Updated
Jun 23, 2025
Vendor
HTML Tidy Advocacy Community Group
Product
HTML Tidy
Classifications
CWE-404, CWE-476, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 23, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 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=5.8.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

HTML Tidy Advocacy Community Group · HTML Tidyversion=5.8.0

Published CVSS scores

3.3VulDBCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
1.9VulDBCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
1.7VulDBAV:L/AC:L/Au:S/C:N/I:N/A:P

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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-404Improper Resource Shutdown or Release
CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

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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