Executive brief
A vulnerability in the Linux kernel's BPF subsystem could allow a local user to crash the system. The issue occurs when running specific network-related BPF test programs that attempt to access uninitialized memory. This results in a kernel panic (system crash), impacting the availability of the affected machine.
Technical details
A null pointer dereference exists in the bpf_lwt_xmit_push_encap helper within the Linux kernel. The vulnerability is triggered when bpf_prog_test_run_skb is used to execute BPF programs of type BPF_PROG_TYPE_LWT_XMIT, as the skb->_skb_refdst field may remain uninitialized. When the helper attempts to access the destination device via skb_dst(skb)->dev to calculate headroom, it encounters a NULL pointer, leading to a kernel oops. The fix involves ensuring the destination reference is properly set before the test run.
Affected products
- Linux Linux kernel Fixed in 5.10.218, 5.15.160, 6.1.92, 6.6.32, 6.8.11, 6.9.2
Timeline
- 2026-03-04: patched: Initial patch submitted by Feng Yang
- 2026-06-24: advisory: CVE-2026-53111 published by NVD
References
- https://git.kernel.org/stable/c/5500913516e071dbe23e5a404c861dd2d82c9589
- https://git.kernel.org/stable/c/599905c3f10bb83e6e6881d5a7f5cea5df07dc23
- https://git.kernel.org/stable/c/5c8d1f91fc4898d79f29d79c1a6f7c2b3ee66fb0
- https://git.kernel.org/stable/c/94f95328b9070909b5b875c647b17a11d3d85567
- https://git.kernel.org/stable/c/972787479ee73006fddb5e59ab5c8e733810ff42
- https://git.kernel.org/stable/c/c7ad31fb948fdd4905263f4324160682c3fa7bc6