A newly disclosed vulnerability called the Safe RET Interrupt Vulnerability has been patched in the Linux kernel. It stems from a flaw in Linux's implementation of the Safe RET mitigation for Speculative Return Stack Overflow (SRSO), affecting AMD Zen 1 through Zen 4 processors. An attacker could inject an interrupt at a precise moment to weaken the SRSO protection, potentially leading to information disclosure. The vulnerability was discovered by researcher Daniël Trujillo at MIT CSAIL, and AMD has confirmed the issue is tied to the Linux implementation. A fix has been merged into the Linux kernel Git tree.
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What is the Safe RET Interrupt Vulnerability in the Linux kernel and which AMD processors are affected?
The Safe RET Interrupt Vulnerability is a flaw in the Linux kernel's implementation of the Safe RET mitigation for Speculative Return Stack Overflow (SRSO). An attacker executing code on an affected system can inject an interrupt at a precise moment to weaken that protection, potentially causing information disclosure. AMD Zen 1 through Zen 4 processors are affected, with Zen 1 and Zen 2 demonstrated and Zen 3/Zen 4 considered likely. A fix has been merged into the Linux kernel Git tree. Engineers maintaining AMD-based Linux systems can track kernel security patches like this one on daily.dev.