CVE-2026-85877: CWE-122: Heap-based Buffer Overflow in Microsoft Windows 11 Version 24H2

CVE-2026-85877 is a heap-based buffer overflow vulnerability classified under CWE-122 affecting Windows Print Spooler components in Windows 11 Version 24H2. An attacker without privileges can remotely execute code by exploiting this flaw over a network. The affected versions are Windows 11 builds starting from 10.0.26100.0 up to but excluding 10.0.26100.9445. The vulnerability has a CVSS 3.1 base score of 8.8, indicating high impact on confidentiality, integrity, and availability. Microsoft has published an official security update to remediate this vulnerability. No active exploitation has been reported.

Successful exploitation allows an unauthenticated attacker to execute arbitrary code remotely on affected Windows 11 systems via the Print Spooler service. This can lead to full system compromise, including complete control over confidentiality, integrity, and availability of the system.

An official security update from Microsoft is available and should be applied immediately to affected Windows 11 Version 24H2 systems. The vendor advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85877 provides detailed patching instructions. No additional mitigations are specified by the vendor.