CVE-2025-6498Public exploit

Process interruption via unreleased parser allocations

Published Jun 23, 2025 · Updated Jun 23, 2025

Memory leak in HTML Tidy 5.8.0 allows local users to consume process memory by parsing a crafted HTML or XML file. The parser creates nodes, attributes, and strings through defaultAlloc in src/alloc.c but fails to release all allocated blocks after parsing. Local ability to supply input to a Tidy process is required, and repeated processing can exhaust memory and interrupt that process.

CVSS severity3.3
Low
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leak in HTML Tidy 5.8.0 allows local users to consume process memory by parsing a crafted HTML or XML file. The parser creates nodes, attributes, and strings through defaultAlloc in src/alloc.c but fails to release all allocated blocks after parsing. Local ability to supply input to a Tidy process is required, and repeated processing can exhaust memory and interrupt that process.

The record

CVE
CVE-2025-6498
Published
Jun 23, 2025
Updated
Jun 23, 2025
Vendor
HTML Tidy Advocacy Community Group
Product
HTML Tidy
Classifications
CWE-401, CWE-404, T1499.004
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

3.3UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

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 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-401Missing Release of Memory after Effective Lifetime
CWE-404Improper Resource Shutdown or Release
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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