CVE-2025-6498: A vulnerability classified as problematic has been found in HTACG tidy-html5 5.8.0

Routine

LOW 3.3DOWNGRADE

CVE-2025-6498 is a low-severity flaw (CVSS 3.3) affecting tidy. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A vulnerability classified as problematic has been found in HTACG tidy-html5 5.8.0. Affected is the function defaultAlloc of the file src/alloc.c. The manipulation leads to memory leak. It is possible to launch the attack on the local host. The exploit has been disclosed to the public and may be used.

Why this priority

Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	3.3 (Low)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 85%)
CISA exploited list	No
Weakness	CWE-401, CWE-404
Published	2025-06-23
Last modified	2026-06-17

Publisher (CNA): VulDB · Vendor: htacg

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

Am I affected?

Timeline

2025-06-23 02:15 UTCPublished CVE record published
2026-06-17 10:02 UTCUpdated Record last modified

htacg tidy DOWNGRADE

Affected: 5.8.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 5.8.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 5.8.0 (Debian / Ubuntu)

apt-cache madison tidy sudo apt install tidy=<VERSION_BEFORE_5.8.0> sudo apt-mark hold tidy

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list tidy sudo dnf downgrade tidy-<VERSION_BEFORE_5.8.0> sudo dnf versionlock add tidy

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2025-6498?

tidy: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2025-6498 being exploited?

CVE-2025-6498 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-2025-6498 affect?

CVE-2025-6498 affects tidy. Severity is low (CVSS 3.3). A vulnerability classified as problematic has been found in HTACG tidy-html5 5.8.0. Affected is the function defaultAlloc of the file src/alloc.c. The manipulation leads to memory leak. It is possible to launch the attack on the local host.

How urgent is CVE-2025-6498?

Priority 20/100. Public exploit reference

References

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