# CVE-2025-38320: arm64/ptrace: Fix stack-out-of-bounds read in regs_get_kernel_stack_nth()

Status: published. Published: 2025-07-10. Updated: 2026-11-05.

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

arm64/ptrace: Fix stack-out-of-bounds read in regs_get_kernel_stack_nth()

KASAN reports a stack-out-of-bounds read in regs_get_kernel_stack_nth().

Call Trace:
[   97.283505] BUG: KASAN: stack-out-of-bounds in regs_get_kernel_stack_nth+0xa8/0xc8
[   97.284677] Read of size 8 at addr ffff800089277c10 by task 1.sh/2550
[   97.285732]
[   97.286067] CPU: 7 PID: 2550 Comm: 1.sh Not tainted 6.6.0+ #11
[   97.287032] Hardware name: linux,dummy-virt (DT)
[   97.287815] Call trace:
[   97.288279]  dump_backtrace+0xa0/0x128
[   97.288946]  show_stack+0x20/0x38
[   97.289551]  dump_stack_lvl+0x78/0xc8
[   97.290203]  print_address_description.constprop.0+0x84/0x3c8
[   97.291159]  print_report+0xb0/0x280
[   97.291792]  kasan_report+0x84/0xd0
[   97.292421]  __asan_load8+0x9c/0xc0
[   97.293042]  regs_get_kernel_stack_nth+0xa8/0xc8
[   97.293835]  process_fetch_insn+0x770/0xa30
[   97.294562]  kprobe_trace_func+0x254/0x3b0
[   97.295271]  kprobe_dispatcher+0x98/0xe0
[   97.295955]  kprobe_breakpoint_handler+0x1b0/0x210
[   97.296774]  call_break_hook+0xc4/0x100
[   97.297451]  brk_handler+0x24/0x78
[   97.298073]  do_debug_exception+0xac/0x178
[   97.298785]  el1_dbg+0x70/0x90
[   97.299344]  el1h_64_sync_handler+0xcc/0xe8
[   97.300066]  el1h_64_sync+0x78/0x80
[   97.300699]  kernel_clone+0x0/0x500
[   97.301331]  __arm64_sys_clone+0x70/0x90
[   97.302084]  invoke_syscall+0x68/0x198
[   97.302746]  el0_svc_common.constprop.0+0x11c/0x150
[   97.303569]  do_el0_svc+0x38/0x50
[   97.304164]  el0_svc+0x44/0x1d8
[   97.304749]  el0t_64_sync_handler+0x100/0x130
[   97.305500]  el0t_64_sync+0x188/0x190
[   97.306151]
[   97.306475] The buggy address belongs to stack of task 1.sh/2550
[   97.307461]  and is located at offset 0 in frame:
[   97.308257]  __se_sys_clone+0x0/0x138
[   97.308910]
[   97.309241] This frame has 1 object:
[   97.309873]  [48, 184) 'args'
[   97.309876]
[   97.310749] The buggy address belongs to the virtual mapping at
[   97.310749]  [ffff800089270000, ffff800089279000) created by:
[   97.310749]  dup_task_struct+0xc0/0x2e8
[   97.313347]
[   97.313674] The buggy address belongs to the physical page:
[   97.314604] page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x14f69a
[   97.315885] flags: 0x15ffffe00000000(node=1|zone=2|lastcpupid=0xfffff)
[   97.316957] raw: 015ffffe00000000 0000000000000000 dead000000000122 0000000000000000
[   97.318207] raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
[   97.319445] page dumped because: kasan: bad access detected
[   97.320371]
[   97.320694] Memory state around the buggy address:
[   97.321511]  ffff800089277b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   97.322681]  ffff800089277b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   97.323846] >ffff800089277c00: 00 00 f1 f1 f1 f1 f1 f1 00 00 00 00 00 00 00 00
[   97.325023]                          ^
[   97.325683]  ffff800089277c80: 00 00 00 00 00 00 00 00 00 f3 f3 f3 f3 f3 f3 f3
[   97.326856]  ffff800089277d00: f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00

This issue seems to be related to the behavior of some gcc compilers and
was also fixed on the s390 architecture before:

 commit d93a855c31b7 ("s390/ptrace: Avoid KASAN false positives in regs_get_kernel_stack_nth()")

As described in that commit, regs_get_kernel_stack_nth() has confirmed that
`addr` is on the stack, so reading the value at `*addr` should be allowed.
Use READ_ONCE_NOCHECK() helper to silence the KASAN check for this case.

[will: Use '*addr' as the argument to READ_ONCE_NOCHECK()]

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 0a8ea52c3eb157dd65e224fc95b7c9c99fcba9f7; < 64773b3ea09235168a549a195cba43bb867c4a17 (affected, git); ≥ 0a8ea52c3eb157dd65e224fc95b7c9c99fcba9f7; < 67abac27d806e8f9d4226ec1528540cf73af673a (affected, git); ≥ 0a8ea52c3eb157dd65e224fc95b7c9c99fcba9f7; < 92750bfe7b0d8dbcaf578c091a65eda1c5f9ad38 (affected, git); ≥ 0a8ea52c3eb157dd65e224fc95b7c9c99fcba9f7; < 01f91d415a8375d85e0c7d3615cd4a168308bb7c (affected, git); ≥ 0a8ea52c3eb157dd65e224fc95b7c9c99fcba9f7; < 21da6d3561f373898349ca7167c9811c020da695 (affected, git); ≥ 0a8ea52c3eb157dd65e224fc95b7c9c99fcba9f7; < 22f935bc86bdfbde04009f05eee191d220cd8c89 (affected, git); ≥ 0a8ea52c3eb157dd65e224fc95b7c9c99fcba9f7; < 422e565b7889ebfd9c8705a3fc786642afe61fca (affected, git); ≥ 0a8ea52c3eb157dd65e224fc95b7c9c99fcba9f7; < 39dfc971e42d886e7df01371cd1bef505076d84c (affected, git). Source: CNA: Linux
- Linux / Linux: 4.8 (affected); ≥ 0; < 4.8 (unaffected, semver); ≥ 5.4.295; ≤ 5.4.* (unaffected, semver); ≥ 5.10.239; ≤ 5.10.* (unaffected, semver); ≥ 5.15.186; ≤ 5.15.* (unaffected, semver); ≥ 6.1.142; ≤ 6.1.* (unaffected, semver); ≥ 6.6.95; ≤ 6.6.* (unaffected, semver); ≥ 6.12.35; ≤ 6.12.* (unaffected, semver); ≥ 6.15.4; ≤ 6.15.* (unaffected, semver); ≥ 6.16; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: 0.21% as of 2026-11-05; percentile 11.26%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/64773b3ea09235168a549a195cba43bb867c4a17 (CNA: Linux)

- https://git.kernel.org/stable/c/67abac27d806e8f9d4226ec1528540cf73af673a (CNA: Linux)

- https://git.kernel.org/stable/c/92750bfe7b0d8dbcaf578c091a65eda1c5f9ad38 (CNA: Linux)

- https://git.kernel.org/stable/c/01f91d415a8375d85e0c7d3615cd4a168308bb7c (CNA: Linux)

- https://git.kernel.org/stable/c/21da6d3561f373898349ca7167c9811c020da695 (CNA: Linux)

- https://git.kernel.org/stable/c/22f935bc86bdfbde04009f05eee191d220cd8c89 (CNA: Linux)

- https://git.kernel.org/stable/c/422e565b7889ebfd9c8705a3fc786642afe61fca (CNA: Linux)

- https://git.kernel.org/stable/c/39dfc971e42d886e7df01371cd1bef505076d84c (CNA: Linux)

- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html (ADP: CVE)

- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html (ADP: CVE)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2025-38320; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2025-38320; retrieved 2026-11-05; source updated Not reported

Revision: 438fcf2e057b81daabd8449513f8cf20e88ea77aa08f45008a5053292c731508

Canonical: https://y2.dev/cve/CVE-2025-38320

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