LegacyUpdate Flaw (CVE-2026-97381) Rated CVSS 9.9
A newly published critical vulnerability in LegacyUpdate carries a CVSS score of 9.9. Here is what is affected and how to respond.
Key points
- CVE-2026-97381 affects LegacyUpdate.
- CVSS 9.9 (Critical).
- No exploitation confirmed yet.
LegacyUpdate is affected by CVE-2026-97381, a security flaw that the National Vulnerability Database rates 9.9 out of 10.
At a glance
- CVE
- CVE-2026-97381
- Product
- LegacyUpdate
- CVSS
- 9.9 Critical
- Weakness
- CWE-346, CWE-393
- Exploited
- No known exploitation
What is the vulnerability?
The NVD entry states: 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.
Affected versions
| Vendor | Product | Versions |
|---|---|---|
| Legacyupdate | LegacyUpdate | >= 1.12.0, < 1.13.2 |
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.
Is it being exploited?
There is no public confirmation of exploitation at the time of publication. It does not appear in CISA's Known Exploited Vulnerabilities catalog. We will update this report if that changes.
What should you do?
- Identify whether the affected product and versions run in your environment.
- Apply the vendor update listed in the advisory as soon as it is available.
- Limit network exposure of the affected service until it is patched.
- Monitor the vendor advisory for updated guidance or exploitation reports.
What to do and how to stay safe: CVE-2026-97381
- Vulnerability severity scores ignore your specific architecture and context.
- Exploitability depends on network exposure and user behavior, not just code flaws.
- Prioritization requires continuous asset inventory and threat intelligence alignment.
Risk-based vulnerability management focuses your limited resources on the flaws that actually threaten your business. Start by mapping your critical assets and checking for active exploits to prioritize your backlog.
Step-by-step guide: Risk-Based Vulnerability Management: Prioritize Fixes by Actual Danger
General security guidance from the Threat Times newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
What is CVE-2026-97381?
CVE-2026-97381 is a CWE-346, CWE-393 vulnerability in LegacyUpdate.
How severe is CVE-2026-97381?
It has a CVSS score of 9.9 Critical.
Is CVE-2026-97381 being exploited?
There is no public confirmation of exploitation at the time of publication.
