CVE-2021-47276: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: ftrace: Do not blindly read the ip address in ftrace_bug() It was reported that a bug on arm64 caused a bad ip address to be used for updating into a nop in ftrace_init(), but the error path (rightfully) returned -EINVAL and not -EFAULT, as the bug caused more than one error to occur. But because -EINVAL was returned, the ftrace_bug() tried to report what was at the location of the ip address, and read it directly. This caused the machine to panic, as the ip was not pointing to a valid memory address. Instead, read the ip address with copy_from_kernel_nofault() to safely access the memory, and if it faults, report that the address faulted, otherwise report what was in that location.

Affected products

• Linux Linux Kernel: from 2.6.28, before 4.4.273 (fixed in 4.4.273); from 4.5, before 4.9.273 (fixed in 4.9.273); from 4.10, before 4.14.237 (fixed in 4.14.237); from 4.15, before 4.19.195 (fixed in 4.19.195); from 4.20, before 5.4.126 (fixed in 5.4.126); from 5.5, before 5.10.44 (fixed in 5.10.44); …

Published 2024-05-21. Last modified 2026-06-17.