Linux Kernel Vulnerability in BPF JIT Allocator

CVE-2026-64508

What is CVE-2026-64508?

A vulnerability exists in the Linux kernel's BPF JIT allocator, which can lead to security risks associated with indirect branch prediction. The issue arises when the allocator reuses memory space previously occupied by different programs, potentially allowing an attacker to exploit branch predictions left from the prior programs. To mitigate this risk, a new mechanism has been introduced to flush indirect branch predictors before reallocating memory in JIT contexts, ensuring that old predictions do not affect new program executions. However, it's crucial to note that allocations larger than a predefined threshold remain unaffected by this flush, justified by the limited nature of cBPF programs. Developers and system administrators should ensure their systems are updated to the latest kernel version to avoid exploitation of this vulnerability.

References