CVE Database›Document archive›CVE-2021-46974

CVE-2021-46974

kernel: bpf: Fix masking negation logic upon negative dst register

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Severity

Moderate

Red Hat Product Security

2.3

CVSS 3.1

Review impact separately from score.

Published · February 27, 2024

Updated · August 5, 2026

Description

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.

Statement

No Red Hat Products are affected by this vulnerability.

CVSS score applicability

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation

No mitigation is specified in collected source.

CVSS / CWE

CVSS 3.1 · 2.3
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L

CWE-20 · Improper Input Validation