CISA Mandates Urgent Patching for Three Actively Exploited Linux Kernel Flaws
CISA has added three Linux kernel vulnerabilities to its Known Exploited Vulnerabilities catalog, ordering federal agencies to patch them by September 23, 2026. The flaws, ranging from medium to critical severity, are being actively exploited in the wild. While CISA has not disclosed details about the threat actors, Red Hat and other vendors have confirmed public exploits exist for two of the issues. The most critical flaw, CVE-2025-39964, has existed in the kernel for 14 years and allows for privilege escalation and container escape.