CVE-2021-29155: Debian Linux

Medium severity, CVSS 5.5. EPSS: 1.1% chance of exploitation in the next 30 days.

An issue was discovered in the Linux kernel through 5.11.x. kernel/bpf/verifier.c performs undesirable out-of-bounds speculation on pointer arithmetic, leading to side-channel attacks that defeat Spectre mitigations and obtain sensitive information from kernel memory. Specifically, for sequences of pointer arithmetic operations, the pointer modification performed by the first operation is not correctly accounted for when restricting subsequent operations.

Affected products

• Debian Debian Linux: version 9.0 only
• Fedoraproject Fedora: version 32 only; version 33 only; version 34 only
• Linux Linux Kernel: before 5.11.16 (fixed in 5.11.16)

Published 2021-04-20. Last modified 2026-06-17.