CVE-2021-33624

In kernel/bpf/verifier.c in the Linux kernel before 5.12.13, a branch can be mispredicted (e.g., because of type confusion) and consequently an unprivileged BPF program can read arbitrary memory locations via a side-channel attack, aka CID-9183671af6db.

CVSS 3.1

4.7CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

EPSS

0.9% chance of exploitation in the next 30 days; higher than 60% of CVEs (scores of 2026-10-25)

CWE

CWE-843

Published

2021-06-23

Modified

2026-10-08

Record from

the NVD, synced 2026-10-19

Affected

• debian:debian_linux
• linux:linux_kernel

References

• http://www.openwall.com/lists/oss-security/2021/06/21/1
• https://github.com/benschlueter/CVE-2021-33624
• https://github.com/torvalds/linux/commit/9183671af6dbf60a1219371d4ed73e23f43b49db
• https://lists.debian.org/debian-lts-announce/2021/10/msg00010.html
• https://www.usenix.org/conference/usenixsecurity21/presentation/kirzner

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