{"cve":"CVE-2023-53326","nvd":{"published":"2025-09-16T17:15:38.783","modified":"2026-06-17T06:44:53.877","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc: Don't try to copy PPR for task with NULL pt_regs\n\npowerpc sets up PF_KTHREAD and PF_IO_WORKER with a NULL pt_regs, which\nfrom my (arguably very short) checking is not commonly done for other\narchs. This is fine, except when PF_IO_WORKER's have been created and\nthe task does something that causes a coredump to be generated. Then we\nget this crash:\n\n  Kernel attempted to read user page (160) - exploit attempt? (uid: 1000)\n  BUG: Kernel NULL pointer dereference on read at 0x00000160\n  Faulting instruction address: 0xc0000000000c3a60\n  Oops: Kernel access of bad area, sig: 11 [#1]\n  LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=32 NUMA pSeries\n  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\n  CPU: 1 PID: 1982 Comm: ppc-crash Not tainted 6.3.0-rc2+ #88\n  Hardware name: IBM pSeries (emulated by qemu) POWER9 (raw) 0x4e1202 0xf000005 of:SLOF,HEAD hv:linux,kvm pSeries\n  NIP:  c0000000000c3a60 LR: c000000000039944 CTR: c0000000000398e0\n  REGS: c0000000041833b0 TRAP: 0300   Not tainted  (6.3.0-rc2+)\n  MSR:  800000000280b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE>  CR: 88082828  XER: 200400f8\n  ...\n  NIP memcpy_power7+0x200/0x7d0\n  LR  ppr_get+0x64/0xb0\n  Call Trace:\n    ppr_get+0x40/0xb0 (unreliable)\n    __regset_get+0x180/0x1f0\n    regset_get_alloc+0x64/0x90\n    elf_core_dump+0xb98/0x1b60\n    do_coredump+0x1c34/0x24a0\n    get_signal+0x71c/0x1410\n    do_notify_resume+0x140/0x6f0\n    interrupt_exit_user_prepare_main+0x29c/0x320\n    interrupt_exit_user_prepare+0x6c/0xa0\n    interrupt_return_srr_user+0x8/0x138\n\nBecause ppr_get() is trying to copy from a PF_IO_WORKER with a NULL\npt_regs.\n\nCheck for a valid pt_regs in both ppc_get/ppr_set, and return an error\nif not set. The actual error value doesn't seem to be important here, so\njust pick -EINVAL.\n\n[mpe: Trim oops in change log, add Fixes & Cc stable]","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-476"],"references":["https://git.kernel.org/stable/c/01849382373b867ddcbe7536b9dfa89f3bcea60e","https://git.kernel.org/stable/c/064a1c7b0f8403260d77627e62424a72ca26cee2","https://git.kernel.org/stable/c/7624973bc15b76d000e8e6f9b8080fcb76d36595","https://git.kernel.org/stable/c/80a4200d51e5a7e046f4a90f5faa5bafd5a60c58","https://git.kernel.org/stable/c/fd7276189450110ed835eb0a334e62d2f1c4e3be"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:10:08.713834912+00:00"},"epss":{"cve":"CVE-2023-53326","score":0.00148,"percentile":0.03984,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}