CVE-2021-46974: 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: bpf: Fix masking negation logic upon negative dst register The negation logic for the case where the off_reg is sitting in the dst register is not correct given then we cannot just invert the add to a sub or vice versa. As a fix, perform the final bitwise and-op unconditionally into AX from the off_reg, then move the pointer from the src to dst and finally use AX as the source for the original pointer arithmetic operation such that the inversion yields a correct result. The single non-AX mov in between is possible given constant blinding is retaining it as it's not an immediate based operation.

Affected products

• Linux Linux Kernel: from 4.14.113, before 4.14.233 (fixed in 4.14.233); from 4.19.19, before 4.19.190 (fixed in 4.19.190); from 5.0, before 5.4.117 (fixed in 5.4.117); from 5.5, before 5.10.35 (fixed in 5.10.35); from 5.11, before 5.11.19 (fixed in 5.11.19); from 5.12, before 5.12.2 (fixed in 5.12.2)

Published 2024-02-27. Last modified 2026-08-04.