CVE-2023-0459

A vulnerability was found in copy_from_user in 64-bit versions of the Linux kernel. This flaw allows a local attacker to bypass the "access_ok" sanity check and pass a kernel pointer to copy_from_user(), resulting in kernel data leaking.

Copy_from_user on 64-bit versions of the Linux kernel does not implement the __uaccess_begin_nospec allowing a user to bypass the "access_ok" check and pass a kernel pointer to copy_from_user(). This would allow an attacker to leak information. We recommend upgrading beyond commit 74e19ef0ff8061ef55957c3abd71614ef0f42f47

It was discovered that the Traffic-Control Index implementation in the Linux kernel did not properly perform filter deactivation in some situations. A local attacker could possibly use this to gain elevated privileges. Please note that with the fix for this CVE, kernel support for the TCINDEX classifier has been removed. It was discovered that some AMD x86-64 processors with SMT enabled could speculatively execute instructions using a return address from a sibling thread. A local attacker could possibly use this to expose sensitive information.