Bug 2464451 (CVE-2026-43010)

Summary: CVE-2026-43010 kernel: bpf: Reject sleepable kprobe_multi programs at attach time
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel. A local user could attach a sleepable BPF kprobe_multi program, which allows sleepable helper functions, such as bpf_copy_from_user(), to be invoked from a non-sleepable context. This incorrect handling can lead to a system crash, resulting in a Denial of Service (DoS).
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Description OSIDB Bzimport 2026-05-01 15:07:33 UTC 
In the Linux kernel, the following vulnerability has been resolved:

bpf: Reject sleepable kprobe_multi programs at attach time

kprobe.multi programs run in atomic/RCU context and cannot sleep.
However, bpf_kprobe_multi_link_attach() did not validate whether the
program being attached had the sleepable flag set, allowing sleepable
helpers such as bpf_copy_from_user() to be invoked from a non-sleepable
context.

This causes a "sleeping function called from invalid context" splat:

  BUG: sleeping function called from invalid context at ./include/linux/uaccess.h:169
  in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1787, name: sudo
  preempt_count: 1, expected: 0
  RCU nest depth: 2, expected: 0

Fix this by rejecting sleepable programs early in
bpf_kprobe_multi_link_attach(), before any further processing.
Comment 1 Keith Grant 2026-05-01 16:14:49 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050154-CVE-2026-43010-aef9@gregkh/T