CVE-2023-53790 bpf: Zeroing allocated object from slab in bpf memory allocator
A race condition in the Linux kernel BPF memory allocator can cause a hard-lockup and denial of service when freed elements are reused.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-53790?
CVE-2023-53790 is a high-severity vulnerability in Linux, published on 9 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
bpf: Zeroing allocated object from slab in bpf memory allocator
Currently the freed element in bpf memory allocator may be immediately reused, for htab map the reuse will reinitialize special fields in map value (e.g., bpf_spin_lock), but lookup procedure may still access these special fields, and it may lead to hard-lockup as shown below:
NMI backtrace for cpu 16 CPU: 16 PID: 2574 Comm: htab.bin Tainted: G L 6.1.0+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), RIP: 0010:queued_spin_lock_slowpath+0x283/0x2c0 ...... Call Trace: <TASK> copy_map_value_locked+0xb7/0x170 bpf_map_copy_value+0x113/0x3c0 __sys_bpf+0x1c67/0x2780 __x64_sys_bpf+0x1c/0x20 do_syscall_64+0x30/0x60 entry_SYSCALL_64_after_hwframe+0x46/0xb0 ...... </TASK>
For htab map, just like the preallocated case, these is no need to initialize these special fields in map value again once these fields have been initialized. For preallocated htab map, these fields are initialized through __GFP_ZERO in bpf_map_area_alloc(), so do the similar thing for non-preallocated htab in bpf memory allocator. And there is no need to use __GFP_ZERO for per-cpu bpf memory allocator, because __alloc_percpu_gfp() does it implicitly.
Which versions are affected by CVE-2023-53790?
How do I fix CVE-2023-53790?
Apply the vendor's patch.
Is CVE-2023-53790 being exploited?
There is no known exploitation of CVE-2023-53790 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2023-53790, DEBIAN-CVE-2023-53790, GHSA-f32h-2m5f-x5c6, UBUNTU-CVE-2023-53790.