Microsoft and the U.S. government have issued a warning about a vulnerability in Windows, designated CVE-2026-20805, which is currently being exploited. This flaw allows an authorized attacker to leak a memory address from a remote ALPC port, potentially leading to arbitrary code execution. It has a medium severity rating of 5.5 on the CVSS scale. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added this vulnerability to its Known Exploited Vulnerabilities catalog and requires federal agencies to implement a patch by February 3.
Additionally, two other vulnerabilities were acknowledged: CVE-2026-21265, a secure boot certificate expiration bypass with a CVSS rating of 6.4, and CVE-2023-31096, an elevation of privilege flaw affecting third-party Agere Modem drivers, rated at 7.8. Two more vulnerabilities, CVE-2026-20952 (CVSS 7.7) and CVE-2026-20953 (CVSS 7.4), are use-after-free flaws in Office that could allow unauthorized code execution.