CVE-2023-53326

MEDIUM EPSS 3.3%

Published Sep 16, 20259mo ago · Modified Jun 17, 20261w ago

5.5 CVSS 3.1

Medium

Published Sep 16, 2025 9mo ago

Last Modified Jun 17, 2026 1w ago

Description

In the Linux kernel, the following vulnerability has been resolved: powerpc: Don't try to copy PPR for task with NULL pt_regs powerpc sets up PF_KTHREAD and PF_IO_WORKER with a NULL pt_regs, which from my (arguably very short) checking is not commonly done for other archs. This is fine, except when PF_IO_WORKER's have been created and the task does something that causes a coredump to be generated. Then we get this crash: Kernel attempted to read user page (160) - exploit attempt? (uid: 1000) BUG: Kernel NULL pointer dereference on read at 0x00000160 Faulting instruction address: 0xc0000000000c3a60 Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=32 NUMA pSeries Modules linked in: bochs drm_vram_helper drm_kms_helper xts binfmt_misc ecb ctr syscopyarea sysfillrect cbc sysimgblt drm_ttm_helper aes_generic ttm sg libaes evdev joydev virtio_balloon vmx_crypto gf128mul drm dm_mod fuse loop configfs drm_panel_orientation_quirks ip_tables x_tables autofs4 hid_generic usbhid hid xhci_pci xhci_hcd usbcore usb_common sd_mod CPU: 1 PID: 1982 Comm: ppc-crash Not tainted 6.3.0-rc2+ #88 Hardware name: IBM pSeries (emulated by qemu) POWER9 (raw) 0x4e1202 0xf000005 of:SLOF,HEAD hv:linux,kvm pSeries NIP: c0000000000c3a60 LR: c000000000039944 CTR: c0000000000398e0 REGS: c0000000041833b0 TRAP: 0300 Not tainted (6.3.0-rc2+) MSR: 800000000280b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 88082828 XER: 200400f8 ... NIP memcpy_power7+0x200/0x7d0 LR ppr_get+0x64/0xb0 Call Trace: ppr_get+0x40/0xb0 (unreliable) __regset_get+0x180/0x1f0 regset_get_alloc+0x64/0x90 elf_core_dump+0xb98/0x1b60 do_coredump+0x1c34/0x24a0 get_signal+0x71c/0x1410 do_notify_resume+0x140/0x6f0 interrupt_exit_user_prepare_main+0x29c/0x320 interrupt_exit_user_prepare+0x6c/0xa0 interrupt_return_srr_user+0x8/0x138 Because ppr_get() is trying to copy from a PF_IO_WORKER with a NULL pt_regs. Check for a valid pt_regs in both ppc_get/ppr_set, and return an error if not set. The actual error value doesn't seem to be important here, so just pick -EINVAL. [mpe: Trim oops in change log, add Fixes & Cc stable]

CVSS Details

Base Score

5.5

Exploitability

1.8

Impact

3.6

Vector string

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector Local

Attack Complexity Low

Privileges Required Low

User Interaction None

Scope Unchanged

Confidentiality None

Integrity None

Availability High

Threat Intelligence

EPSS Exploit Probability

3.3% percentile

Exploit & Patch Status

No Known Exploit

Patch Available

Weaknesses 1

CWE-476 NULL Pointer Dereference Memory Safety

Affected Products 8

Vendor	Product	Version	Range
linux	linux_kernel	*	≥4.8 – <5.10.177
linux	linux_kernel	*	≥5.11 – <5.15.106
linux	linux_kernel	*	≥5.16 – <6.1.23
linux	linux_kernel	*	≥6.2 – <6.2.10
linux	linux_kernel	6.3	any
linux	linux_kernel	6.3	any
linux	linux_kernel	6.3	any
linux	linux_kernel	6.3	any

References 5

git.kernel.org https://git.kernel.org/stable/c/01849382373b867ddcbe7536b9dfa89f3bcea60e

Patch
git.kernel.org https://git.kernel.org/stable/c/064a1c7b0f8403260d77627e62424a72ca26cee2

Patch
git.kernel.org https://git.kernel.org/stable/c/7624973bc15b76d000e8e6f9b8080fcb76d36595

Patch
git.kernel.org https://git.kernel.org/stable/c/80a4200d51e5a7e046f4a90f5faa5bafd5a60c58

Patch
git.kernel.org https://git.kernel.org/stable/c/fd7276189450110ed835eb0a334e62d2f1c4e3be

Patch

Remediation

git.kernel.org https://git.kernel.org/stable/c/01849382373b867ddcbe7536b9dfa89f3bcea60e

Patch
git.kernel.org https://git.kernel.org/stable/c/064a1c7b0f8403260d77627e62424a72ca26cee2

Patch
git.kernel.org https://git.kernel.org/stable/c/7624973bc15b76d000e8e6f9b8080fcb76d36595

Patch
git.kernel.org https://git.kernel.org/stable/c/80a4200d51e5a7e046f4a90f5faa5bafd5a60c58

Patch
git.kernel.org https://git.kernel.org/stable/c/fd7276189450110ed835eb0a334e62d2f1c4e3be

Patch