{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-90046", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.783Z", "datePublished": "2026-09-16T10:33:43.156Z", "dateUpdated": "2026-10-19T08:57:04.231Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:57:04.231Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/page_alloc: don't spin_trylock() in NMI on UP\n\nPatch series \"mm/page_alloc: fixes for free_pages_nolock() on RT/UP\".\n\nPre-existing bugs found by Sashiko during review of this other series:\nhttps://lore.kernel.org/all/20260703-alloc-trylock-v5-0-c87b714e19d3@google.com/\n\nI have not reproduced these bugs, and I suspect there is no real-world\nuser that is affected by them.\n\n\nThis patch (of 2):\n\nAs noted in can_spin_trylock(), using this is unsafe in this context. \ncommit 620b46ed6ae17 (\"mm/page_alloc: return NULL early from\nalloc_frozen_pages_nolock() in NMI on UP\") fixed this on the alloc side\nbut missed the free side.\n\nImpact: If BPF programs using these features in NMI (probably tracing) are\npresent on non-SMP builds this might crash the kernel and is probably\nexploitable by local attackers for privilege escalation." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - free_pages_nolock is reached from local BPF programs (arena/bpf_map_alloc_pages and related nolock helpers) running in NMI, typically a BPF_PROG_TYPE_PERF_EVENT overflow handler installed via bpf()/perf_event_open. It is not reachable from unauthenticated network packets or in-kernel servers such as ksmbd/nfsd.\nAC:L - Scoring assumes a uniprocessor (!CONFIG_SMP) kernel, a reasonable embedded/IoT deployment. An attacker who can attach a BPF perf-event program controls the NMI that calls free_pages_nolock and can concurrently run page-allocator work so the NMI interrupts zone->lock; the in-tree slub_kunit NMI overflow test shows this reentry is reliably triggerable.\nPR:L - Loading the NMI BPF program requires CAP_BPF and CAP_PERFMON, which are sub-root capabilities. BPF tokens can delegate those checks into a non-init user namespace in plausible container/tracing deployments, so this is treated as low privileges rather than init-namespace root.\nUI:N - The attacker loads the BPF program, programs the PMU, and drives local memory activity themselves. No separate victim action such as mounting a filesystem or opening a crafted file is required.\nS:U - Re-entrant buddy/zone-lock corruption stays inside the kernel's own security authority and yields local privilege escalation, not a VM, IOMMU, or other cross-boundary escape.\nC:H - Nested spin_trylock of zone->lock on UP lets the NMI mutate buddy freelists while the interrupted context is mid-update, corrupting page-allocator metadata. That overlapping-page primitive can be leveraged for arbitrary kernel memory disclosure.\nI:H - The same freelist corruption is a well-known arbitrary-write and control-flow hijack primitive, and the fix commit states the bug is probably exploitable by local attackers for privilege escalation.\nA:H - Re-entrant zone-lock and buddy updates crash the kernel via oops, panic, or a DEBUG_SPINLOCK BUG on UP, which is a full availability loss." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "mm/page_alloc.c" ], "versions": [ { "version": "8c57b687e8331eb80e302a2c528b18b966a9ac7a", "lessThan": "06c76d3c389ff504052f64b1acee44651bd847fa", "status": "affected", "versionType": "git" }, { "version": "8c57b687e8331eb80e302a2c528b18b966a9ac7a", "lessThan": "68a069b407303e71db371df85036101e8ff59280", "status": "affected", "versionType": "git" }, { "version": "8c57b687e8331eb80e302a2c528b18b966a9ac7a", "lessThan": "3105ae628fb785d48b49256468be4f21a7b3cfc0", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "mm/page_alloc.c" ], "versions": [ { "version": "6.15", "status": "affected" }, { "version": "0", "lessThan": "6.15", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.51", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.5", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "6.18.51" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.2.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/06c76d3c389ff504052f64b1acee44651bd847fa" }, { "url": "https://git.kernel.org/stable/c/68a069b407303e71db371df85036101e8ff59280" }, { "url": "https://git.kernel.org/stable/c/3105ae628fb785d48b49256468be4f21a7b3cfc0" } ], "title": "mm/page_alloc: don't spin_trylock() in NMI on UP", "x_generator": { "engine": "bippy-1.2.0" } } } }