143 lines
8.6 KiB
JSON
143 lines
8.6 KiB
JSON
{
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"dataType": "CVE_RECORD",
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"dataVersion": "5.2",
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"cveMetadata": {
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"cveId": "CVE-2026-23342",
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"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"state": "PUBLISHED",
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"assignerShortName": "Linux",
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"dateReserved": "2026-01-13T15:37:45.999Z",
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"datePublished": "2026-03-25T10:27:30.285Z",
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"dateUpdated": "2026-05-11T22:04:59.186Z"
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},
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"containers": {
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"cna": {
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"providerMetadata": {
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"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"shortName": "Linux",
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"dateUpdated": "2026-05-11T22:04:59.186Z"
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},
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"descriptions": [
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{
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"lang": "en",
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix race in cpumap on PREEMPT_RT\n\nOn PREEMPT_RT kernels, the per-CPU xdp_bulk_queue (bq) can be accessed\nconcurrently by multiple preemptible tasks on the same CPU.\n\nThe original code assumes bq_enqueue() and __cpu_map_flush() run\natomically with respect to each other on the same CPU, relying on\nlocal_bh_disable() to prevent preemption. However, on PREEMPT_RT,\nlocal_bh_disable() only calls migrate_disable() (when\nPREEMPT_RT_NEEDS_BH_LOCK is not set) and does not disable\npreemption, which allows CFS scheduling to preempt a task during\nbq_flush_to_queue(), enabling another task on the same CPU to enter\nbq_enqueue() and operate on the same per-CPU bq concurrently.\n\nThis leads to several races:\n\n1. Double __list_del_clearprev(): after bq->count is reset in\n bq_flush_to_queue(), a preempting task can call bq_enqueue() ->\n bq_flush_to_queue() on the same bq when bq->count reaches\n CPU_MAP_BULK_SIZE. Both tasks then call __list_del_clearprev()\n on the same bq->flush_node, the second call dereferences the\n prev pointer that was already set to NULL by the first.\n\n2. bq->count and bq->q[] races: concurrent bq_enqueue() can corrupt\n the packet queue while bq_flush_to_queue() is processing it.\n\nThe race between task A (__cpu_map_flush -> bq_flush_to_queue) and\ntask B (bq_enqueue -> bq_flush_to_queue) on the same CPU:\n\n Task A (xdp_do_flush) Task B (cpu_map_enqueue)\n ---------------------- ------------------------\n bq_flush_to_queue(bq)\n spin_lock(&q->producer_lock)\n /* flush bq->q[] to ptr_ring */\n bq->count = 0\n spin_unlock(&q->producer_lock)\n bq_enqueue(rcpu, xdpf)\n <-- CFS preempts Task A --> bq->q[bq->count++] = xdpf\n /* ... more enqueues until full ... */\n bq_flush_to_queue(bq)\n spin_lock(&q->producer_lock)\n /* flush to ptr_ring */\n spin_unlock(&q->producer_lock)\n __list_del_clearprev(flush_node)\n /* sets flush_node.prev = NULL */\n <-- Task A resumes -->\n __list_del_clearprev(flush_node)\n flush_node.prev->next = ...\n /* prev is NULL -> kernel oops */\n\nFix this by adding a local_lock_t to xdp_bulk_queue and acquiring it\nin bq_enqueue() and __cpu_map_flush(). These paths already run under\nlocal_bh_disable(), so use local_lock_nested_bh() which on non-RT is\na pure annotation with no overhead, and on PREEMPT_RT provides a\nper-CPU sleeping lock that serializes access to the bq.\n\nTo reproduce, insert an mdelay(100) between bq->count = 0 and\n__list_del_clearprev() in bq_flush_to_queue(), then run reproducer\nprovided by syzkaller."
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}
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],
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"affected": [
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "unaffected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"kernel/bpf/cpumap.c"
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],
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"versions": [
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{
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"version": "3253cb49cbad4772389d6ef55be75db1f97da910",
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"lessThan": "7466ae2aeed483de80c5d8dea0913cf74038b652",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "3253cb49cbad4772389d6ef55be75db1f97da910",
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"lessThan": "e67299e1044349ad0088d52c6bc5764cc1816c06",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "3253cb49cbad4772389d6ef55be75db1f97da910",
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"lessThan": "869c63d5975d55e97f6b168e885452b3da20ea47",
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"status": "affected",
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"versionType": "git"
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}
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]
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},
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "affected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"kernel/bpf/cpumap.c"
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],
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"versions": [
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{
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"version": "6.18",
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"status": "affected"
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},
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{
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"version": "0",
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"lessThan": "6.18",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.18.17",
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"lessThanOrEqual": "6.18.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.19.7",
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"lessThanOrEqual": "6.19.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.0",
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"lessThanOrEqual": "*",
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"status": "unaffected",
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"versionType": "original_commit_for_fix"
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}
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]
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}
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],
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"cpeApplicability": [
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{
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"nodes": [
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{
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"operator": "OR",
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"negate": false,
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"cpeMatch": [
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "6.18",
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"versionEndExcluding": "6.18.17"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "6.18",
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"versionEndExcluding": "6.19.7"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "6.18",
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"versionEndExcluding": "7.0"
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}
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]
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}
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]
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}
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],
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"references": [
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{
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"url": "https://git.kernel.org/stable/c/7466ae2aeed483de80c5d8dea0913cf74038b652"
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},
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{
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"url": "https://git.kernel.org/stable/c/e67299e1044349ad0088d52c6bc5764cc1816c06"
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},
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{
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"url": "https://git.kernel.org/stable/c/869c63d5975d55e97f6b168e885452b3da20ea47"
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}
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],
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"title": "bpf: Fix race in cpumap on PREEMPT_RT",
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"x_generator": {
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"engine": "bippy-1.2.0"
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}
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}
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}
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} |