CVE-2026-41091: Microsoft Defender Link Following Vulnerability — Fixed versions

Summary

Microsoft Defender contains a link following vulnerability that allows an authorized attacker to elevate privileges locally.

Remediation

Inventory every Microsoft Defender deployment, including staging.
Upgrade Microsoft Defender to 1.1.26040.8.
Confirm the running version after the upgrade.
Review logs from before the change for signs of exploitation.

CISA required actionApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

References

Patchhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-41091
Advisoryhttps://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-41091
Advisoryhttps://nvd.nist.gov/vuln/detail/CVE-2026-41091
Referencehttps://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-41091