PT-2021-8281 · Unknown+4 · Htacg Html Tidy+4

Published 2021-05-05 · Updated 2025-03-18 · CVE-2021-33391

Positive Technologies (AI Summary)

CVSS v2.0

10

Critical

Base vector

AV:N/AC:L/Au:N/C:C/I:C/A:C

Name of the Vulnerable Software and Affected Versions HTACG HTML Tidy version 5.7.28

Description The issue allows an attacker to execute arbitrary code via the -g option of the CleanNode() function in gdoc.c. This is related to a use-after-free vulnerability in the CleanNode() function of the gdoc.c component. Exploitation of this issue may allow a remote attacker to cause a denial of service.

Recommendations For HTACG HTML Tidy version 5.7.28, consider disabling the CleanNode() function as a temporary workaround until a patch is available. Restrict access to the gdoc.c component to minimize the risk of exploitation. At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

Use After Free

Weakness Enumeration

CWE-416

Related Identifiers

AZL-13687

AZL-35324

BDU:2025-00970

CVE-2021-33391

OESA-2024-1017

OESA-2024-1073

ROSA-SA-2025-2658

USN-6483-1

Affected Products

Astra Linux

Debian

Htacg Html Tidy

Linuxmint

Ubuntu

References · 26

• 🔥 https://github.com/htacg/tidy-html5/issues/946 · Exploit
• https://osv.dev/vulnerability/OESA-2024-1073 · Vendor Advisory
• https://osv.dev/vulnerability/AZL-13687 · Vendor Advisory
• https://osv.dev/vulnerability/AZL-35324 · Vendor Advisory
• https://osv.dev/vulnerability/USN-6483-1 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2021-33391 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2021-33391 · Vendor Advisory
• https://ubuntu.com/security/notices/USN-6483-1 · Vendor Advisory
• https://ubuntu.com/security/CVE-2021-33391 · Vendor Advisory
• https://wiki.astralinux.ru/astra-linux-se47-bulletin-2025-0422SE80 · Vendor Advisory
• https://osv.dev/vulnerability/OESA-2024-1017 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-33391 · Security Note
• https://wiki.astralinux.ru/astra-linux-se18-bulletin-2025-0114SE18MD · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2021-33391 · Security Note
• https://osv.dev/vulnerability/DEBIAN-CVE-2021-33391 · Vendor Advisory