{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2024-44973", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-08-21T05:34:56.669Z", "datePublished": "2024-09-04T19:00:23.444Z", "dateUpdated": "2026-08-05T11:37:23.425Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:37:23.425Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm, slub: do not call do_slab_free for kfence object\n\nIn 782f8906f805 the freeing of kfence objects was moved from deep\ninside do_slab_free to the wrapper functions outside. This is a nice\nchange, but unfortunately it missed one spot in __kmem_cache_free_bulk.\n\nThis results in a crash like this:\n\nBUG skbuff_head_cache (Tainted: G S B E ): Padding overwritten. 0xffff88907fea0f00-0xffff88907fea0fff @offset=3840\n\nslab_err (mm/slub.c:1129)\nfree_to_partial_list (mm/slub.c:? mm/slub.c:4036)\nslab_pad_check (mm/slub.c:864 mm/slub.c:1290)\ncheck_slab (mm/slub.c:?)\nfree_to_partial_list (mm/slub.c:3171 mm/slub.c:4036)\nkmem_cache_alloc_bulk (mm/slub.c:? mm/slub.c:4495 mm/slub.c:4586 mm/slub.c:4635)\nnapi_build_skb (net/core/skbuff.c:348 net/core/skbuff.c:527 net/core/skbuff.c:549)\n\nAll the other callers to do_slab_free appear to be ok.\n\nAdd a kfence_free check in __kmem_cache_free_bulk to avoid the crash." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - The primary and reported trigger is the NIC receive softirq path — `napi_build_skb()` → `napi_skb_cache_get()` → `kmem_cache_alloc_bulk(skbuff_cache, GFP_ATOMIC, …)` — driven entirely by inbound packets, with the same remote traffic flood supplying the GFP_ATOMIC pressure that makes the bulk allocation fail mid-array. No local access is needed to reach the vulnerable free path.\nAC:H - Exploitation requires KFENCE to be active with a non-zero sample interval, the timer-driven `kfence_allocation_gate` (~10 allocations/second system-wide) to land on one of the attacker's bulk-allocation slots, and that same bulk allocation to then fail at a later index — the KFENCE sampling gate is a periodic timer the attacker cannot influence, so the required coincidence is beyond attacker control.\nPR:N - The network receive path is reached by any packet arriving on a NIC using `napi_build_skb()`/`napi_alloc_skb()`, with no authentication, credentials, or local account required.\nUI:N - The bulk skb allocation path runs autonomously in softirq context on packet receipt; no victim action of any kind is needed.\nS:U - The corruption is confined to the kernel's own slab allocator metadata and heap; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - A KFENCE pool page is inserted into a live cache's partial list, so SLUB subsequently hands out memory aliasing other subsystems' live KFENCE-guarded objects, and free hooks read `obj_exts[]` out of bounds into static kernel data — both allow disclosure of arbitrary kernel memory contents.\nI:H - `set_freepointer()` writes past the KFENCE object into the redzone/guard page, `slab->inuse` underflows to 65535, and the aliased pool page lets the allocator return the same memory to two owners, plus out-of-bounds `obj_exts[]` writes into `kfence_metadata_init[]` — a full heap corruption primitive suitable for control-flow hijacking.\nA:H - The reported real-world effect is a slab corruption BUG (`Padding overwritten` / `check_slab`) and kernel crash; without debug enabled, allocations served from unmapped KFENCE guard pages and the NULL `slab_cache` on the injected page cause oopses and panics." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "mm/slub.c" ], "versions": [ { "version": "782f8906f8057efc7151b4b98b0a0280a71d005f", "lessThan": "b35cd7f1e969aaa63e6716d82480f6b8a3230949", "status": "affected", "versionType": "git" }, { "version": "782f8906f8057efc7151b4b98b0a0280a71d005f", "lessThan": "a371d558e6f3aed977a8a7346350557de5d25190", "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/slub.c" ], "versions": [ { "version": "6.8", "status": "affected" }, { "version": "0", "lessThan": "6.8", "status": "unaffected", "versionType": "semver" }, { "version": "6.10.5", "lessThanOrEqual": "6.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.11", "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": "6.8", "versionEndExcluding": "6.10.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "6.11" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/b35cd7f1e969aaa63e6716d82480f6b8a3230949" }, { "url": "https://git.kernel.org/stable/c/a371d558e6f3aed977a8a7346350557de5d25190" } ], "title": "mm, slub: do not call do_slab_free for kfence object", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2024-44973", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2024-09-10T17:39:02.040290Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-09-12T17:33:34.160Z" } } ] } }