CVE-2024-50102

Name of the Vulnerable Software and Affected Versions: Linux kernel (affected versions not specified)

Description: The issue is related to a "Meltdown Lite" problem with non-canonical accesses in kernel space, which can lead to the leakage of speculative data. This is due to the use of just the high bit to decide whether an access is in user space or kernel space. The kernel has been updated to surround the access with a STAC/CLAC pair, which serializes execution on older Zen architectures and closes the speculation window. However, this is not effective on Zen 5 architectures, which rename the AC bit and improve the performance of STAC/CLAC, but also open the speculation window. The issue affects the new address masking, as well as the regular valid user address() check used by access ok(), and the asm version of the sign bit check in the get user() helpers.

Recommendations: At the moment, there is no information about a newer version that contains a fix for this vulnerability.