CVE-2026-64163 test_kprobes: clear kprobes between test runs

What is CVE-2026-64163?

CVE-2026-64163 is a medium-severity denial of service vulnerability in Linux kernel, published on 19 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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

test_kprobes: clear kprobes between test runs

Running the kprobes sanity tests twice makes all tests fail and eventually crashes the kernel.

[root@martin-riscv-1 ~]# echo 1 > /sys/kernel/debug/kunit/kprobes_test/run ... # Totals: pass:5 fail:0 skip:0 total:5 ok 1 kprobes_test [root@martin-riscv-1 ~]# echo 1 > /sys/kernel/debug/kunit/kprobes_test/run ... # test_kprobe: EXPECTATION FAILED at lib/tests/test_kprobes.c:64 Expected 0 == register_kprobe(&kp), but register_kprobe(&kp) == -22 (0xffffffffffffffea) ... Unable to handle kernel paging request ...

The testsuite defines several kprobes and kretprobes as static variables that are preserved across test runs.

After register_kprobe and unregister_kprobe, a kprobe contains some leftover data that must be cleared before the kprobe can be registered again. The tests are setting symbol_name to define the probe location. Address and flags must be cleared.

The existing code clears some of the probes between subsequent tests, but not between two test runs. The leftover data from a previous test run makes the registrations fail in the next run.

Move the cleanups for all kprobes into kprobes_test_init, this function is called before each single test (including the first test of a test run).

Which versions are affected by CVE-2026-64163?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-64163?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-64163 being exploited?

There is no known exploitation of CVE-2026-64163 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2026-64163, DEBIAN-CVE-2026-64163, GHSA-9292-g249-69fp, UBUNTU-CVE-2026-64163.