A logic bug flaw was found in Linux kernel before 5.8-rc1 in the implementation of SSBD. A bug in the logic handling allows an attacker with a local account to disable SSBD protection during a context switch when additional speculative execution mitigations are in place. This issue was introduced when the per task/process conditional STIPB switching was added on top of the existing SSBD switching. The highest threat from this vulnerability is to confidentiality.

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-10766
• https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2020-10766
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=dbbe2ad02e9df26e372f38cc3e70dab9222c832e