{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-98813", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.371Z", "datePublished": "2026-10-18T15:48:59.745Z", "dateUpdated": "2026-10-19T09:26:06.490Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:26:06.490Z" }, "descriptions": [ { "lang": "en", "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." } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/bpf/hashtab.c" ], "versions": [ { "version": "1df97a7453eec80c1912c2d0360290a3970a7671", "lessThan": "b506f5699e145196ee29d76cf1ca1cbb2202c055", "status": "affected", "versionType": "git" }, { "version": "1df97a7453eec80c1912c2d0360290a3970a7671", "lessThan": "ab39974240a0cff765f3bb9cce81d8001ffdb144", "status": "affected", "versionType": "git" }, { "version": "451a84a3ad3c897c03181af433e7c98640730f1f", "status": "affected", "versionType": "git" }, { "version": "51a17f0ce19c4ee2a25cf16c93490d509b1ebb0a", "status": "affected", "versionType": "git" }, { "version": "6.12.112", "lessThan": "6.13", "status": "affected", "versionType": "semver" }, { "version": "6.18.55", "lessThan": "6.19", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/bpf/hashtab.c" ], "versions": [ { "version": "7.0", "status": "affected" }, { "version": "0", "lessThan": "7.0", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.10", "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": "7.0", "versionEndExcluding": "7.2.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.0", "versionEndExcluding": "7.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.112" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18.55" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/b506f5699e145196ee29d76cf1ca1cbb2202c055" }, { "url": "https://git.kernel.org/stable/c/ab39974240a0cff765f3bb9cce81d8001ffdb144" } ], "title": "bpf: Hold map BTF for the memory allocator destructor record", "x_generator": { "engine": "bippy-1.2.0" } } } }