CVE-2026-10677 Kernel heap memory leak in `z_vrfy_k_poll()` lets an unprivileged user thread exhaust the kernel resource pool
An unprivileged user thread can exhaust the kernel heap via a memory leak in the poll syscall verifier, causing system-wide denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-10677?
CVE-2026-10677 is a medium-severity denial of service vulnerability in Zephyrproject Zephyr, published on 21 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
The CONFIG_USERSPACE syscall verifier z_vrfy_k_poll() in kernel/poll.c allocates a kernel-side copy of the user-supplied k_poll_event[] via z_thread_malloc() and then validates each event's object handle. Before this fix, validation used K_OOPS(K_SYSCALL_OBJ(...)) inline inside the loop, which kills the calling thread without freeing events_copy.
A user thread can pass num_events >= 1 with a forged object handle to leak the allocation; because newly spawned user threads inherit the parent's resource_pool (kernel/thread.c), an attacker spawns sacrificial threads to repeat the leak until the shared kernel heap is exhausted. Once depleted, legitimate kernel allocations from that pool (k_queue alloc nodes, k_msgq buffers, future k_poll calls, etc.) fail, causing a system-level denial of service.
The fix replaces each inline K_OOPS with a conditional goto oops_free so the buffer is freed before the thread is killed. Affects Zephyr releases from v1.12.0 (when k_poll was first exposed to user mode) through v4.4.1.
Weakness: CWE-401
Which versions are affected by CVE-2026-10677?
It affects 1 product.
Products include Zephyrproject Zephyr.
How do I fix CVE-2026-10677?
No fix has been published for CVE-2026-10677 yet. Limit exposure of the affected software until one is available.
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-2026-10677 being exploited?
There is no known exploitation of CVE-2026-10677 in the wild and no public exploit code.
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Sources
Also known as GHSA-r3cc-8wcr-xfj9.