CVE-2026-22994: bpf: Fix reference count leak in bpf_prog_test_run_xdp()

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-01-23 · updated 2026-10-15

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix reference count leak in bpf_prog_test_run_xdp() syzbot is reporting unregister_netdevice: waiting for sit0 to become free. Usage count = 2 problem. A debug printk() patch found that a refcount is obtained at xdp_convert_md_to_buff() from bpf_prog_test_run_xdp(). According to commit ec94670fcb3b ("bpf: Support specifying ingress via xdp_md context in BPF_PROG_TEST_RUN"), the refcount obtained by xdp_convert_md_to_buff() will be released by xdp_convert_buff_to_md(). Therefore, we can consider that the error handling path introduced by commit 1c1949982524 ("bpf: introduce frags support to bpf_prog_test_run_xdp()") forgot to call xdp_convert_buff_to_md().

Affected products

Linux kernel: from 5.18 before 6.1.161; from 6.2 before 6.6.121; from 6.7 before 6.12.66; from 6.13 before 6.18.6; 6.19-rc1, 6.19-rc2, 6.19-rc3, 6.19-rc4, 6.19-rc5 — fixed in 6.1.161, 6.12.66, 6.18.6, 6.6.121

How to fix

Upgrade to a fixed version: Linux kernel 6.1.161, 6.12.66, 6.18.6, 6.6.121. Check the vendor advisory for mitigations.

References

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