CVE-2026-74338

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

bpf: Reject sleepable BPF_LSM_CGROUP programs at load time

The cgroup shim runs under rcu_read_lock_dont_migrate(), so we should

not attach any sleepable BPF programs there. Add support to the verifier

to explicitly reject attempts to load sleepable BPF programs destined

for LSM cgroup attachment.

Without this, we get the following splat from a BPF_LSM_CGROUP

program marked BPF_F_SLEEPABLE attached to file_open when it calls

bpf_get_dentry_xattr():

BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1567

in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 34317, name: load

preempt_count: 0, expected: 0

RCU nest depth: 2, expected: 0

Call Trace:

down_read+0x76/0x480

ext4_xattr_get+0x11f/0x700

__vfs_getxattr+0xf0/0x150

bpf_get_dentry_xattr+0xbb/0xf0

bpf_prog_e76a298dac9218c6_test_open+0x6a/0x85

__cgroup_bpf_run_lsm_current+0x326/0x840

bpf_trampoline_644253464

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References