CVE-2025-68322 parisc: Avoid crash due to unaligned access in unwinder
A local attacker can cause a kernel deadlock and system crash on PA-RISC architectures by triggering unaligned memory access in the stack unwinder.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Not stated
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-68322?
CVE-2025-68322 is a denial of service vulnerability in Linux, published on 16 Dec 2025.
Official description
In the Linux kernel, the following vulnerability has been resolved:
parisc: Avoid crash due to unaligned access in unwinder
Guenter Roeck reported this kernel crash on his emulated B160L machine:
Starting network: udhcpc: started, v1.36.1 Backtrace: [<104320d4>] unwind_once+0x1c/0x5c [<10434a00>] walk_stackframe.isra.0+0x74/0xb8 [<10434a6c>] arch_stack_walk+0x28/0x38 [<104e5efc>] stack_trace_save+0x48/0x5c [<105d1bdc>] set_track_prepare+0x44/0x6c [<105d9c80>] ___slab_alloc+0xfc4/0x1024 [<105d9d38>] __slab_alloc.isra.0+0x58/0x90 [<105dc80c>] kmem_cache_alloc_noprof+0x2ac/0x4a0 [<105b8e54>] __anon_vma_prepare+0x60/0x280 [<105a823c>] __vmf_anon_prepare+0x68/0x94 [<105a8b34>] do_wp_page+0x8cc/0xf10 [<105aad88>] handle_mm_fault+0x6c0/0xf08 [<10425568>] do_page_fault+0x110/0x440 [<10427938>] handle_interruption+0x184/0x748 [<11178398>] schedule+0x4c/0x190 BUG: spinlock recursion on CPU#0, ifconfig/2420 lock: terminate_lock.2+0x0/0x1c, .magic: dead4ead, .owner: ifconfig/2420, .owner_cpu: 0
While creating the stack trace, the unwinder uses the stack pointer to guess the previous frame to read the previous stack pointer from memory. The crash happens, because the unwinder tries to read from unaligned memory and as such triggers the unalignment trap handler which then leads to the spinlock recursion and finally to a deadlock.
Fix it by checking the alignment before accessing the memory.
Which versions are affected by CVE-2025-68322?
How do I fix CVE-2025-68322?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-68322 being exploited?
There is no known exploitation of CVE-2025-68322 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2025-68322, DEBIAN-CVE-2025-68322, GHSA-5cpg-hfmf-h5fh, ROOT-OS-DEBIAN-11-CVE-2025-68322, ROOT-OS-DEBIAN-12-CVE-2025-68322, ROOT-OS-DEBIAN-13-CVE-2025-68322 and 3 more.