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Fencer Vulns
no cvss —

CVE-2026-72028 json

riscv: probes: save original sp in rethook trampoline

published 2026-08-15 2 mo ago modified 2026-10-30 9 d ago also EUVD-2026-58986

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 11%
public exploits
0
none known

Summary

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 ... [<ffffffff80016d16>] regs_get_kernel_stack_nth+0x26/0x38 [<ffffffff80177196>] process_fetch_insn+0x3ee/0x760 [<ffffffff80177836>] kretprobe_trace_func+0x116/0x1f0 [<ffffffff8017795a>] kretprobe_dispatcher+0x4a/0x58 [<ffffffff8013572e>] kretprobe_rethook_handler+0x5e/0x90 [<ffffffff80180838>] rethook_trampoline_handler+0x70/0x108 [<ffffffff8001ba32>] arch_rethook_trampoline_callback+0x12/0x1c [<ffffffff8001ba84>] arch_rethook_trampoline+0x48/0x94 [<ffffffff8067872a>] 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]

Patch / fix

  • Linux Linux 6.1.191, 6.6.145, 6.12.97, 6.18.40, 7.1.5, 7.2
  • linux Debian 13 6.12.100-1
  • linux Debian 14 7.1.5-1

debian advisories DEBIAN-CVE-2026-72028

  • linux Ubuntu 24.04 LTS 6.8.0-147.147
  • linux Ubuntu 26.04 LTS 7.0.0-38.38
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1067.70
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1014.14
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1071.79
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1014.14
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1066.74
  • linux-gke Ubuntu 26.04 LTS 7.0.0-1008.9

ubuntu advisories UBUNTU-CVE-2026-72028

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-72028 updated cvss 5.5

kernel: riscv: probes: save original sp in rethook trampoline

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-08).

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

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