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GHSA-RJ58-8R73-76RG

Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-15 06:32
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

riscv: probes: save original sp in rethook trampoline

Reading a word from the stack in a kretprobe crashes a risc-v kernel.

$ cd /sys/kernel/tracing/ $ echo 'r n_tty_write $stack0' > dynamic_events $ echo 1 > events/kprobes/enable Unable to handle kernel paging request at virtual address 0000000200000128 ... [] regs_get_kernel_stack_nth+0x26/0x38 [] process_fetch_insn+0x3ee/0x760 [] kretprobe_trace_func+0x116/0x1f0 [] kretprobe_dispatcher+0x4a/0x58 [] kretprobe_rethook_handler+0x5e/0x90 [] rethook_trampoline_handler+0x70/0x108 [] arch_rethook_trampoline_callback+0x12/0x1c [] arch_rethook_trampoline+0x48/0x94 [] tty_write+0x1a/0x30

In regs_get_kernel_stack_nth, regs->sp contains an arbitrary value.

arch_rethook_trampoline saves the registers from the probed function in a struct pt_regs. sp is not saved. Instead, sp is decremented for arch_rethook_trampoline's local stack.

Fix this crash and save the original sp along with the other registers. Use a0 as a temporary register, it is overwritten anyway.

[pjw@kernel.org: added Fixes tag; cc'ed stable]

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2026-72028"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T06:21:01Z",
    "severity": null
  },
  "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 \u0027r n_tty_write $stack0\u0027 \u003e dynamic_events\n$ 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\u0027s 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\u0027ed stable]",
  "id": "GHSA-rj58-8r73-76rg",
  "modified": "2026-08-15T06:32:09Z",
  "published": "2026-08-15T06:32:09Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72028"
    },
    {
      "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"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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