CVE-2026-80916 is a vulnerability in Linux Kernel
Published on September 9, 2026
kcov: fix data corruption and race conditions on PREEMPT_RT
In the Linux kernel, the following vulnerability has been resolved:
kcov: fix data corruption and race conditions on PREEMPT_RT
syzbot is reporting KCOV state corruption on PREEMPT_RT kernels, for the
temporary storage used for saving/restoring remote KCOV state is currently
allocated as the per-CPU area.
On PREEMPT_RT kernels, softirq handlers run as preemptible task threads
(e.g., ksoftirqd). If a softirq context preempts a task running a remote
KCOV session, it safely saves the task's state into the per-CPU area.
However, if that softirq thread is subsequently preempted by a higher-
priority softirq thread on the same CPU, the second softirq will overwrite
the same per-CPU area, permanently destroying the original task's KCOV
state.
Fix this data corruption by moving the temporary storage from the per-CPU
area to the per-thread area. Since each softirq thread now owns its own
task context, nested softirq preemption no longer causes data overwrites.
Note that while the temporary storage is now on a per-thread basis, the
per-CPU kcov_percpu_data.lock must be retained, for we need to ensure that
kcov_remote_start() and kcov_remote_stop() operate atomically without
racing against asynchronous interrupts that manipulate the current task's
KCOV state.
It is likely that GFP_KERNEL allocation by vmalloc_node() in kcov_init()
has already called panic() before returning NULL, for there will be no
OOM-killable userspace processes when __init function of built-in module
runs. But this patch also fixes crashing the kernel when vmalloc_node()
in kcov_init() returned NULL, for kcov_init() left per-CPU irq_area == NULL
but kcov_remote_start() depends on per-CPU irq_area != NULL, resulting in
(1) doing vmalloc() in kcov_remote_start() despite !in_task() context
(2) out-of-array-bounds access if (1) succeeded but
kcov->remote_size < CONFIG_KCOV_IRQ_AREA_SIZE
(3) always leak memory allocated by (1), eventually killing all
OOM-killable userspace processes
problems.
Products Associated with CVE-2026-80916
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Affected Versions
Linux:- Version 5ff3b30ab57da82d8db4f14662a2858cabfbc2c0 and below ef7048d8a614c5f5a9b20513a5428101a744514e is affected.
- Version 5ff3b30ab57da82d8db4f14662a2858cabfbc2c0 and below 8ed3ddf23d39bf5338406bd9f8863d44748cf6ce is affected.
- Version 5ff3b30ab57da82d8db4f14662a2858cabfbc2c0 and below 5dc59fc959b2b5742985d7ef24bccd1868217dc2 is affected.
- Version 5ff3b30ab57da82d8db4f14662a2858cabfbc2c0 and below a2fb8222cde23b0001812ed3acb7c0ea36dd94e2 is affected.
- Version 5ff3b30ab57da82d8db4f14662a2858cabfbc2c0 and below 18799e858b407bf355383c9dd6c06477aa437134 is affected.
- Version 5ff3b30ab57da82d8db4f14662a2858cabfbc2c0 and below e11f5b48c82703242a3be7a7ae4b4940b4cb4610 is affected.
- Version 5ff3b30ab57da82d8db4f14662a2858cabfbc2c0 and below 22670d1552fe155822b2abf91f920925f7d067b4 is affected.
- Version 5ff3b30ab57da82d8db4f14662a2858cabfbc2c0 and below f8c9a3ec36b4ee3d4701b9be08f40e7bfbf89761 is affected.
- Version 5ff3b30ab57da82d8db4f14662a2858cabfbc2c0 and below 2eed77fdcb0cc48e8eccb2bcd4b7f2c6d650e84c is affected.
- Version 5.8 is affected.
- Before 5.8 is unaffected.
- Version 5.10.269, <= 5.10.* is unaffected.
- Version 5.15.220, <= 5.15.* is unaffected.
- Version 6.1.185, <= 6.1.* is unaffected.
- Version 6.6.154, <= 6.6.* is unaffected.
- Version 6.12.106, <= 6.12.* is unaffected.
- Version 6.18.47, <= 6.18.* is unaffected.
- Version 7.1.11, <= 7.1.* is unaffected.
- Version 7.2.1, <= 7.2.* is unaffected.
- Version 7.3-rc1, <= * is unaffected.