138 lines
8.1 KiB
JSON
138 lines
8.1 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-2024-49573",
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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": "2025-01-11T12:32:49.536Z",
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"datePublished": "2025-01-11T12:35:37.625Z",
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"dateUpdated": "2026-08-05T11:40:03.481Z"
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},
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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": "2026-08-05T11:40:03.481Z"
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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\nsched/fair: Fix NEXT_BUDDY\n\nAdam reports that enabling NEXT_BUDDY insta triggers a WARN in\npick_next_entity().\n\nMoving clear_buddies() up before the delayed dequeue bits ensures\nno ->next buddy becomes delayed. Further ensure no new ->next buddy\never starts as delayed."
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}
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],
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"metrics": [
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{
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"cvssV3_1": {
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"version": "3.1",
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"vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
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"baseScore": 7,
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"baseSeverity": "HIGH"
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},
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"scenarios": [
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{
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"lang": "en",
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"value": "AV:L - The defect is in the CFS scheduler core (kernel/sched/fair.c), reached by ordinary task wakeup, sleep and load-balancer migration on the local machine. There is no remote or adjacent-network input involved, so an attacker must be able to run code on the system.\nAC:H - The entire bug is gated on the NEXT_BUDDY scheduler feature, which is `SCHED_FEAT(NEXT_BUDDY, false)` — disabled by default and settable only by root writing /sys/kernel/debug/sched/features on a CONFIG_SCHED_DEBUG=y kernel (sched_feat_write is the sole caller of sched_feat_set; there is no cmdline or sysctl path). An unprivileged attacker cannot create this precondition, and enabling NEXT_BUDDY is rare in practice, so success depends on system state outside the attacker's control.\nPR:L - Given a system with NEXT_BUDDY enabled, no special capability is needed — any unprivileged task's ordinary sleep/wake and the kernel's own load balancer (attach_task()/move_queued_task() calling wakeup_preempt() on a still-sched_delayed task) drive the code path. Only the ability to run an unprivileged process is required.\nUI:N - No victim action is needed; the reporter observed the WARN triggering instantly on ordinary system activity once the feature was enabled. Normal scheduling and CPU load balancing reach the faulty path on their own.\nS:U - The corrupted state is the kernel's own per-CPU cfs_rq bookkeeping and sched_entity flags, all within the kernel's security authority. No VM, IOMMU, or sandbox boundary is crossed.\nC:H - The scheduler is left able to run an entity that is simultaneously marked sched_delayed and blocked, which desynchronizes on_rq/nr_running/load.weight and can drive __dequeue_entity() to rb_erase an already-unlinked node, writing through a stale rb_parent pointer into memory that may have been reused. Such scheduler-structure corruption is leverageable toward reading kernel memory contents.\nI:H - A task in a non-RUNNING state is made to execute — a direct violation of a core scheduling invariant — and the resulting sched_delayed/on_rq desync leads to double account_entity_dequeue() (nr_running and load.weight underflow) and rb_erase on an unlinked rbtree node, giving a write primitive over scheduler-adjacent memory rather than a mere miscount.\nA:H - pick_next_entity() fires WARN_ONCE, which is a full kernel panic on the panic_on_warn=1 configurations used by hardened and CI deployments, and further SCHED_WARN_ONs cascade in dequeue_entity()/dequeue_entities(). Beyond the splat, the runqueue accounting underflow and rbtree corruption destabilize scheduling on the affected CPU, causing starvation, hangs, and crashes."
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}
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]
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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/sched/fair.c"
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],
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"versions": [
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{
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"version": "152e11f6df293e816a6a37c69757033cdc72667d",
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"lessThan": "5dbe6816c49197677a5ecce749bd99929da147da",
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"status": "affected",
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}
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{
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"product": "Linux",
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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/sched/fair.c"
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],
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"versions": [
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{
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"version": "6.12",
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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": "6.12",
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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": "6.12.7",
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"lessThanOrEqual": "6.12.*",
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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": "6.13",
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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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"versionStartIncluding": "6.12",
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"versionEndExcluding": "6.12.7"
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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": "6.12",
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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/5dbe6816c49197677a5ecce749bd99929da147da"
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},
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{
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"url": "https://git.kernel.org/stable/c/493afbd187c4c9cc1642792c0d9ba400c3d6d90d"
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}
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],
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"title": "sched/fair: Fix NEXT_BUDDY",
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