CVE-2026-80916
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.
Leer descripción completaMostrar menos
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
problems.
Detalles técnicos trazas, registros y código del informe original
(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 processesCVSS
NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.24%
- Percentil entre todas las CVEs puntuadas: 14
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
- https://git.kernel.org/stable/c/18799e858b407bf355383c9dd6c06477aa437134
- https://git.kernel.org/stable/c/22670d1552fe155822b2abf91f920925f7d067b4
- https://git.kernel.org/stable/c/2eed77fdcb0cc48e8eccb2bcd4b7f2c6d650e84c
- https://git.kernel.org/stable/c/5dc59fc959b2b5742985d7ef24bccd1868217dc2
- https://git.kernel.org/stable/c/8ed3ddf23d39bf5338406bd9f8863d44748cf6ce
- https://git.kernel.org/stable/c/a2fb8222cde23b0001812ed3acb7c0ea36dd94e2
- https://git.kernel.org/stable/c/e11f5b48c82703242a3be7a7ae4b4940b4cb4610
- https://git.kernel.org/stable/c/ef7048d8a614c5f5a9b20513a5428101a744514e
- https://git.kernel.org/stable/c/f8c9a3ec36b4ee3d4701b9be08f40e7bfbf89761
JSON original (NVD)
Mostrar
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"id": "CVE-2026-80916",
"cveTags": [],
"metrics": {},
"affected": [
{
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"published": "2026-09-09T17:17:46.513",
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"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nkcov: fix data corruption and race conditions on PREEMPT_RT\n\nsyzbot is reporting KCOV state corruption on PREEMPT_RT kernels, for the\ntemporary storage used for saving/restoring remote KCOV state is currently\nallocated as the per-CPU area.\n\nOn PREEMPT_RT kernels, softirq handlers run as preemptible task threads\n(e.g., ksoftirqd). If a softirq context preempts a task running a remote\nKCOV session, it safely saves the task's state into the per-CPU area.\nHowever, if that softirq thread is subsequently preempted by a higher-\npriority softirq thread on the same CPU, the second softirq will overwrite\nthe same per-CPU area, permanently destroying the original task's KCOV\nstate.\n\nFix this data corruption by moving the temporary storage from the per-CPU\narea to the per-thread area. Since each softirq thread now owns its own\ntask context, nested softirq preemption no longer causes data overwrites.\n\nNote that while the temporary storage is now on a per-thread basis, the\nper-CPU kcov_percpu_data.lock must be retained, for we need to ensure that\nkcov_remote_start() and kcov_remote_stop() operate atomically without\nracing against asynchronous interrupts that manipulate the current task's\nKCOV state.\n\nIt is likely that GFP_KERNEL allocation by vmalloc_node() in kcov_init()\nhas already called panic() before returning NULL, for there will be no\nOOM-killable userspace processes when __init function of built-in module\nruns. But this patch also fixes crashing the kernel when vmalloc_node()\nin kcov_init() returned NULL, for kcov_init() left per-CPU irq_area == NULL\nbut kcov_remote_start() depends on per-CPU irq_area != NULL, resulting in\n\n (1) doing vmalloc() in kcov_remote_start() despite !in_task() context\n\n (2) out-of-array-bounds access if (1) succeeded but\n kcov->remote_size < CONFIG_KCOV_IRQ_AREA_SIZE\n\n (3) always leak memory allocated by (1), eventually killing all\n OOM-killable userspace processes\n\nproblems."
}
],
"lastModified": "2026-09-09T17:17:46.513",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}