How severe is CVE-2026-97381?

CVE-2026-97381 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-97381 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-97381?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-97381 published?

CVE-2026-97381 was published on 2026-10-13 and last updated on 2026-10-17.

CVE-2026-97381

CVE-2026-97381 is a critical-severity vulnerability with a CVSS 3.x base score of 9.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-346.

Key facts

Severity: Critical (CVSS 3.x base score 9.9)
EPSS exploit prediction: 0% (11th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-346
Published: 2026-10-13
Last modified: 2026-10-17

Description

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.

Frequently asked questions

What is CVE-2026-97381?: 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.
How severe is CVE-2026-97381?: CVE-2026-97381 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-97381 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-97381?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-97381 published?: CVE-2026-97381 was published on 2026-10-13 and last updated on 2026-10-17.

References

Other CWE-346 vulnerabilities

CVE-2026-42901 — Critical (CVSS 10.0): Origin validation error in Microsoft Entra ID allows an unauthorized attacker to elevate privileges over a network.
CVE-2026-84140 — Critical (CVSS 9.8): Site isolation issue in the DOM: Navigation component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2,…
CVE-2026-84133 — Critical (CVSS 9.8): Site isolation issue in the DOM: Push Subscriptions component. This vulnerability was fixed in Firefox 155, Firefox ESR…
CVE-2026-84129 — Critical (CVSS 9.8): Site isolation issue in the DOM: Navigation component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2,…
CVE-2026-16375 — Critical (CVSS 9.8): Site isolation issue in the Networking: HTTP component. This vulnerability was fixed in Firefox 153, Firefox ESR…
CVE-2026-16358 — Critical (CVSS 9.8): Site isolation issue in the Graphics: WebRender component. This vulnerability was fixed in Firefox 153, Firefox ESR…

Browse all CWE-346 vulnerabilities →