PT-2021-4648 · Microsoft · Windows Mshtml Platform+1

Published 2021-06-08 · Updated 2025-10-29 · CVE-2021-33742

Positive Technologies (AI Summary)

CVSS v2.0

9.3

High

Base vector

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

Name of the Vulnerable Software and Affected Versions Windows MSHTML Platform (affected versions not specified)

Description The issue is related to a buffer overflow in memory, allowing a remote attacker to execute arbitrary code. This can affect the system and potentially lead to information disclosure or privilege escalation. There have been reports of real-world attacks exploiting this issue, with Google TAG noting its use by a state-sponsored APT against targets in Eastern Europe and the Middle East. Additionally, Kaspersky reported that two privilege escalation vulnerabilities were part of a complex exploit chain used by a new actor, PuzzleMaker, in attacks on several companies.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

RCE

Buffer Overflow

Memory Corruption

Weakness Enumeration

CWE-119

CWE-787

Related Identifiers

BDU:2021-05340

CVE-2021-33742

Affected Products

Windows

Windows Mshtml Platform

References · 20

• https://osv.dev/vulnerability/CVE-2021-33742 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-33742 · Security Note
• https://msrc.microsoft.com/update-guide/en-US/advisory/CVE-2021-33742 · Vendor Advisory
• http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-33742 · Security Note
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33742 · Vendor Advisory
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-33742 · Vendor Advisory
• https://bdu.fstec.ru/vul/2021-05340 · Security Note
• https://t.me/true_secator/1926 · Telegram Post
• https://t.me/true_secator/1805 · Telegram Post
• https://t.me/club1337/886 · Telegram Post
• https://t.me/cvenotify/112276 · Telegram Post
• https://t.me/cveNotify/140860 · Telegram Post
• https://t.me/cvenotify/87763 · Telegram Post
• https://t.me/cvenotify/109940 · Telegram Post
• https://cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-33742 · Note