CVE-2026-46196 tracepoint: balance regfunc() on func_add() failure in tracepoint_add_func()

What is CVE-2026-46196?

CVE-2026-46196 is a medium-severity denial of service vulnerability in Linux kernel, published on 28 May 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:

tracepoint: balance regfunc() on func_add() failure in tracepoint_add_func()

When a tracepoint goes through the 0 -> 1 transition, tracepoint_add_func() invokes the subsystem's ext->regfunc() before attempting to install the new probe via func_add(). If func_add() then fails (for example, when allocate_probes() cannot allocate a new probe array under memory pressure and returns -ENOMEM), the function returns the error without calling the matching ext->unregfunc(), leaving the side effects of regfunc() behind with no installed probe to justify them.

For syscall tracepoints this is particularly unpleasant: syscall_regfunc() bumps sys_tracepoint_refcount and sets SYSCALL_TRACEPOINT on every task. After a leaked failure, the refcount is stuck at a non-zero value with no consumer, and every task continues paying the syscall trace entry/exit overhead until reboot. Other subsystems providing regfunc()/unregfunc() pairs exhibit similarly scoped persistent state.

Mirror the existing 1 -> 0 cleanup and call ext->unregfunc() in the func_add() error path, gated on the same condition used there so the unwind is symmetric with the registration.

Which versions are affected by CVE-2026-46196?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-46196?

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-2026-46196 being exploited?

There is no known exploitation of CVE-2026-46196 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 AZL-89079, BELL-CVE-2026-46196, DEBIAN-CVE-2026-46196, GHSA-3j98-4vrc-2fpm, ROOT-OS-DEBIAN-11-CVE-2026-46196, ROOT-OS-DEBIAN-12-CVE-2026-46196 and 3 more.