{"id":"DEBIAN-CVE-2023-53326","details":"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 \u003cSF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE\u003e  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]","modified":"2026-09-15T09:02:54.013164977Z","published":"2025-09-16T17:15:38.783Z","upstream":["CVE-2023-53326"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2023-53326"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.25-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-53326.json"}},{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.25-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-53326.json"}},{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.25-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-53326.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}