{"id":"CVE-2026-72028","title":"riscv: probes: save original sp in rethook trampoline","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nriscv: probes: save original sp in rethook trampoline\n\nReading a word from the stack in a kretprobe crashes a risc-v kernel.\n\n$ cd /sys/kernel/tracing/\n$ echo 'r n_tty_…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= c22b0bcb1dd024cb9caad9230e3a387d8b061df5 < d21109fe4a55247094f913773a334772907cd016","Linux >= c22b0bcb1dd024cb9caad9230e3a387d8b061df5 < 5da5cf48a432e30ded8d58087854e5383a36eff1","Linux >= c22b0bcb1dd024cb9caad9230e3a387d8b061df5 < c386e1c591d72eab58ee2e69105c8cbc70928857","Linux >= c22b0bcb1dd024cb9caad9230e3a387d8b061df5 < 2faf0198168d2017cb528a79f76c560fda3b6e94","Linux >= c22b0bcb1dd024cb9caad9230e3a387d8b061df5 < 91b4d76dd07f1a1f20f73dfebb42ba04ac911a56","Linux >= c22b0bcb1dd024cb9caad9230e3a387d8b061df5 < bc7b086a45521a986a49045907f017e3e46c763e","Linux 5.12"],"published":"2026-08-15","updated":"2026-10-30","sourceUpdated":"2026-10-30T12:28:45.873Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72028","references":[{"url":"https://git.kernel.org/stable/c/d21109fe4a55247094f913773a334772907cd016"},{"url":"https://git.kernel.org/stable/c/5da5cf48a432e30ded8d58087854e5383a36eff1"},{"url":"https://git.kernel.org/stable/c/c386e1c591d72eab58ee2e69105c8cbc70928857"},{"url":"https://git.kernel.org/stable/c/2faf0198168d2017cb528a79f76c560fda3b6e94"},{"url":"https://git.kernel.org/stable/c/91b4d76dd07f1a1f20f73dfebb42ba04ac911a56"},{"url":"https://git.kernel.org/stable/c/bc7b086a45521a986a49045907f017e3e46c763e"}],"tags":["cve.org"],"epss":0.00215,"epssPercentile":0.11898,"ingestedAt":"2026-11-05T15:02:32.472Z","slug":"CVE-2026-72028","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nriscv: probes: save original sp in rethook trampoline\n\nReading a word from the stack in a kretprobe crashes a risc-v kernel.\n\n$ cd /sys/kernel/tracing/\n$ echo 'r n_tty_write $stack0' > dynamic_events\n$ echo 1 > events/kprobes/enable\nUnable to handle kernel paging request at virtual address 0000000200000128\n...\n[<ffffffff80016d16>] regs_get_kernel_stack_nth+0x26/0x38\n[<ffffffff80177196>] process_fetch_insn+0x3ee/0x760\n[<ffffffff80177836>] kretprobe_trace_func+0x116/0x1f0\n[<ffffffff8017795a>] kretprobe_dispatcher+0x4a/0x58\n[<ffffffff8013572e>] kretprobe_rethook_handler+0x5e/0x90\n[<ffffffff80180838>] rethook_trampoline_handler+0x70/0x108\n[<ffffffff8001ba32>] arch_rethook_trampoline_callback+0x12/0x1c\n[<ffffffff8001ba84>] arch_rethook_trampoline+0x48/0x94\n[<ffffffff8067872a>] tty_write+0x1a/0x30\n\nIn regs_get_kernel_stack_nth, regs->sp contains an arbitrary value.\n\narch_rethook_trampoline saves the registers from the probed function in a\nstruct pt_regs. sp is not saved. Instead, sp is decremented for\narch_rethook_trampoline's local stack.\n\nFix this crash and save the original sp along with the other registers.\nUse a0 as a temporary register, it is overwritten anyway.\n\n[pjw@kernel.org: added Fixes tag; cc'ed stable]\n\n## Affected\n\n- `Linux >= c22b0bcb1dd024cb9caad9230e3a387d8b061df5 < d21109fe4a55247094f913773a334772907cd016`\n- `Linux >= c22b0bcb1dd024cb9caad9230e3a387d8b061df5 < 5da5cf48a432e30ded8d58087854e5383a36eff1`\n- `Linux >= c22b0bcb1dd024cb9caad9230e3a387d8b061df5 < c386e1c591d72eab58ee2e69105c8cbc70928857`\n- `Linux >= c22b0bcb1dd024cb9caad9230e3a387d8b061df5 < 2faf0198168d2017cb528a79f76c560fda3b6e94`\n- `Linux >= c22b0bcb1dd024cb9caad9230e3a387d8b061df5 < 91b4d76dd07f1a1f20f73dfebb42ba04ac911a56`\n- `Linux >= c22b0bcb1dd024cb9caad9230e3a387d8b061df5 < bc7b086a45521a986a49045907f017e3e46c763e`\n- `Linux 5.12`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}