{"id":"CVE-2026-72028","summary":"riscv: probes: save original sp in rethook trampoline","details":"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_write $stack0' \u003e dynamic_events\n$ echo 1 \u003e events/kprobes/enable\nUnable to handle kernel paging request at virtual address 0000000200000128\n...\n[\u003cffffffff80016d16\u003e] regs_get_kernel_stack_nth+0x26/0x38\n[\u003cffffffff80177196\u003e] process_fetch_insn+0x3ee/0x760\n[\u003cffffffff80177836\u003e] kretprobe_trace_func+0x116/0x1f0\n[\u003cffffffff8017795a\u003e] kretprobe_dispatcher+0x4a/0x58\n[\u003cffffffff8013572e\u003e] kretprobe_rethook_handler+0x5e/0x90\n[\u003cffffffff80180838\u003e] rethook_trampoline_handler+0x70/0x108\n[\u003cffffffff8001ba32\u003e] arch_rethook_trampoline_callback+0x12/0x1c\n[\u003cffffffff8001ba84\u003e] arch_rethook_trampoline+0x48/0x94\n[\u003cffffffff8067872a\u003e] tty_write+0x1a/0x30\n\nIn regs_get_kernel_stack_nth, regs-\u003esp 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]","modified":"2026-08-18T03:31:26.341824144Z","published":"2026-08-15T05:51:51.868Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72028.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/2faf0198168d2017cb528a79f76c560fda3b6e94"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5da5cf48a432e30ded8d58087854e5383a36eff1"},{"type":"WEB","url":"https://git.kernel.org/stable/c/91b4d76dd07f1a1f20f73dfebb42ba04ac911a56"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bc7b086a45521a986a49045907f017e3e46c763e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c386e1c591d72eab58ee2e69105c8cbc70928857"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72028.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72028"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"c22b0bcb1dd024cb9caad9230e3a387d8b061df5"},{"fixed":"5da5cf48a432e30ded8d58087854e5383a36eff1"},{"fixed":"c386e1c591d72eab58ee2e69105c8cbc70928857"},{"fixed":"2faf0198168d2017cb528a79f76c560fda3b6e94"},{"fixed":"91b4d76dd07f1a1f20f73dfebb42ba04ac911a56"},{"fixed":"bc7b086a45521a986a49045907f017e3e46c763e"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72028.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.12.0"},{"fixed":"6.6.145"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.97"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.40"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.5"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72028.json"}}],"schema_version":"1.9.0"}