CVE-2026-97381

CRITICAL 9.9

Legacy Update ActiveX control accepts unauthorized hosting origins

CVSS Score

9.9

EPSS Score

0.0%

EPSS Percentile

0th

Legacy Update is a tool for activating and installing updates on legacy Windows PCs. Legacy Update 1.12.0 through 1.13.1 contains an origin validation error in the IsPermitted method of its ActiveX control. After successfully reading the hosting document's hostname, a hostname that is not on the permitted list falls through without setting E_ACCESSDENIED, causing IsPermitted to return S_OK. An attacker who induces a user to visit a malicious webpage in Internet Explorer can invoke the control to enumerate update and system information, install updates without consent, display dialogs, or restart the computer when a reboot is pending. This issue was fixed in Legacy Update 1.13.2.

CWE	CWE-346 CWE-393
Vendor	legacyupdate
Product	legacyupdate
Published	Oct 13, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Affected Versions

LegacyUpdate / LegacyUpdate

>= 1.12.0, < 1.13.2

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/LegacyUpdate/LegacyUpdate/security/advisories/GHSA-f4g7-4gmx-jfgf github.com: https://github.com/LegacyUpdate/LegacyUpdate/commit/7d62f0bfaa770d74cd6e2cb0bac9c1907df48033 github.com: https://github.com/LegacyUpdate/LegacyUpdate/commit/ae1c46c97f39a55a1937784d9f9beb30aa9147fd github.com: https://github.com/LegacyUpdate/LegacyUpdate/releases/tag/v1.13.2.0 legacyupdate.net: https://legacyupdate.net/news/2026/07/21/legacy-update-1-13-2