154 lines
9.0 KiB
JSON
154 lines
9.0 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-2026-98813",
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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": "2026-09-25T10:25:14.371Z",
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"datePublished": "2026-10-18T15:48:59.745Z",
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"dateUpdated": "2026-10-19T09:26:06.490Z"
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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": "2026-10-19T09:26:06.490Z"
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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: Hold map BTF for the memory allocator destructor record\n\nbpf_ma_set_dtor() duplicates map->record so that the bpf_mem_alloc\ndestructor can release the special fields of hash and rhash map elements\nonce the allocator frees them for good. btf_record_dup() only acquires\nreferences on kernel and module BTF. Fields whose types live in the map\nBTF keep pointing into it: a kptr to a local type refers to map->btf,\nand a list_head or rb_root field carries a value_rec owned by the struct\nmeta table of map->btf.\n\nThat borrowed state can outlive the map. When RCU callbacks are still in\nflight, bpf_mem_alloc_destroy() copies the allocator and defers the final\ndrain, together with the destructor context, to a workqueue.\nbpf_map_free() then frees map->record and drops the map's BTF reference\nas soon as map_free() returns. Once the program that loaded the BTF is\ngone as well, the BTF is freed while the worker still uses the\nduplicate. The worker dereferences it through btf_is_kernel() and\nbtf_find_struct_meta() in bpf_obj_free_fields() when destroying elements\nthat were freed under RCU, and through btf_is_kernel() in\nbtf_record_free() when releasing the context itself:\n\n BUG: KASAN: slab-use-after-free in btf_is_kernel+0x19/0x30\n Read of size 1 at addr ffff88811505dce8 by task kworker/u16:2/50\n Workqueue: events_unbound free_mem_alloc_deferred\n Call Trace:\n btf_is_kernel+0x19/0x30\n btf_record_free+0xc7/0xf0\n htab_dtor_ctx_free+0x1a/0x30\n free_mem_alloc_no_barrier+0x39/0x230\n free_mem_alloc_deferred+0x2a/0x40\n process_scheduled_works+0x5ce/0x9d0\n worker_thread+0x42a/0x5e0\n kthread+0x1f5/0x230\n ret_from_fork+0x1dd/0x390\n ret_from_fork_asm+0x1a/0x30\n\n Allocated by task 358:\n __kmalloc_cache_noprof+0x287/0x510\n btf_new_fd+0xf7/0x3d0\n __sys_bpf+0x487/0x840\n\n Freed by task 0:\n kfree+0x186/0x560\n rcu_core+0x6f6/0xd40\n\nFreeing a map that still holds more elements than the allocator's high\nwatermark is enough to get there, because the bulk free during teardown\nqueues the RCU callback that makes bpf_mem_alloc_destroy() defer.\nNon-preallocated hash maps and resizable hash maps both register the\ndestructor and are affected alike.\n\nKeep one reference on the map BTF in the destructor context. Every\nnon-kernel pointer in the duplicated record is either map->btf or memory\nowned by it, so a single reference covers kptrs, list heads, and rb\nroots, and mirrors what bpf_map_meta_alloc() does for the duplicated\nrecord of an inner map. Release it only after the duplicated record has\nbeen freed: the worker is preemptible and not in an RCU read-side\ncritical section, so dropping the last reference first would let the\nBTF be freed while btf_record_free() still reads its fields."
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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/hashtab.c"
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],
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"versions": [
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{
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"version": "1df97a7453eec80c1912c2d0360290a3970a7671",
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"lessThan": "b506f5699e145196ee29d76cf1ca1cbb2202c055",
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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": "1df97a7453eec80c1912c2d0360290a3970a7671",
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"lessThan": "ab39974240a0cff765f3bb9cce81d8001ffdb144",
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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": "451a84a3ad3c897c03181af433e7c98640730f1f",
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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": "51a17f0ce19c4ee2a25cf16c93490d509b1ebb0a",
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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": "6.12.112",
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"lessThan": "6.13",
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"status": "affected",
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"versionType": "semver"
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},
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{
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"version": "6.18.55",
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"lessThan": "6.19",
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"status": "affected",
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"versionType": "semver"
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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/hashtab.c"
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],
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"versions": [
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{
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"version": "7.0",
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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": "7.0",
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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": "7.2.10",
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"lessThanOrEqual": "7.2.*",
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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": "7.3",
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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": "7.0",
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"versionEndExcluding": "7.2.10"
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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": "7.0",
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"versionEndExcluding": "7.3"
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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": "6.12.112"
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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": "6.18.55"
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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/b506f5699e145196ee29d76cf1ca1cbb2202c055"
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},
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{
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"url": "https://git.kernel.org/stable/c/ab39974240a0cff765f3bb9cce81d8001ffdb144"
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}
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],
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"title": "bpf: Hold map BTF for the memory allocator destructor record",
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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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} |