{"id":"CVE-2026-80916","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-80916","generatedAt":"2026-10-28T01:49:06.225Z","title":"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…","description":"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.","published":"2026-09-09T17:17:47.000Z","lastModified":"2026-10-19T09:17:22.000Z","status":"Received","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":null,"cwe":[],"affected":[],"epss":{"score":0.00182,"percentile":0.07699,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"unknown","text":"Not yet scored. NVD analysis is pending; check back once CVSS and EPSS values are published."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/18799e858b407bf355383c9dd6c06477aa437134","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/22670d1552fe155822b2abf91f920925f7d067b4","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/2eed77fdcb0cc48e8eccb2bcd4b7f2c6d650e84c","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5dc59fc959b2b5742985d7ef24bccd1868217dc2","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8ed3ddf23d39bf5338406bd9f8863d44748cf6ce","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a2fb8222cde23b0001812ed3acb7c0ea36dd94e2","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e11f5b48c82703242a3be7a7ae4b4940b4cb4610","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ef7048d8a614c5f5a9b20513a5428101a744514e","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f8c9a3ec36b4ee3d4701b9be08f40e7bfbf89761","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-80916","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}