CVE-2026-64579

The vulnerability lies in the Linux kernel’s xfrm policy hash rebuild routine. An inverted guard causes the routine to pre‑allocate bins for the wrong set of policies, leading to a failure path that warns only and leaves a poisoned list node. When the next rebuild deletes that node, a null pointer dereference occurs, producing a kernel panic via a general protection fault. This crash immediately stops the operating system, creating a denial‑of‑service liability for any system running the affected kernel.

Linux kernel versions that contain the flawed xfrm_hash_rebuild implementation are impacted. No specific release scope is given, so all kernels prior to the patch referenced in the advisory may be vulnerable. The included CPE identifies the generic Linux Kernel product.

Based on the description, it is inferred that the vulnerability can be triggered by actions that cause the xfrm policy table to be rebuilt under memory pressure. This is a local condition that an attacker with host access could potentially manipulate via network policy changes or module loading. Exploitation would result in a kernel crash, but no evidence of remote code execution is present. The EPSS score of < 1% indicates a very low probability of exploitation, and the CVE is not listed in CISA’s KEV catalog. The CVSS score of 5.5 indicates medium severity, so the crash represents a moderate risk denial‑of‑service rather than a critical one.