{"id":"CVE-2024-50246","state":"PUBLISHED","title":"fs/ntfs3: Add rough attr alloc_size check","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nfs/ntfs3: Add rough attr alloc_size check","publishedAt":"2024-11-09T10:14:55.218Z","updatedAt":"2026-10-15T00:57:29.321Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux 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Add rough attr alloc_size check","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nfs/ntfs3: Add rough attr alloc_size 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- The vulnerable parser only processes MFT records read from a mounted NTFS block device, reached via mount(2) and subsequent local filesystem operations, with no network-facing path. Attack Vector is therefore Local rather than Physical, since the attacker supplies the image data and does not need to touch the hardware themselves.\nAC:L - The attacker fully controls the on-disk `alloc_size` field in the crafted image, so the oversized-allocation path is triggered deterministically at mount time with no race, timing, or memory-layout dependency (syzbot has a reproducer). No conditions lie outside the attacker's control.\nPR:N - The attacker needs no account or privileges on the target system — they only need to hand over a malicious NTFS image or removable device, which is then mounted by an administrator or automatically by a desktop automounter such as udisks2. All parsing happens before any attacker credential is involved.\nUI:R - Some action on the victim's side is required to bring the crafted volume into the kernel — mounting the image, inserting the removable device, or opening a file on such a volume. The bug cannot fire without that step.\nS:U - The corruption and resource exhaustion are confined to the kernel of the machine performing the mount; no VM, IOMMU, or other security-authority boundary is crossed. This is a standard in-kernel filesystem parsing flaw.\nC:H - The unvalidated 64-bit `alloc_size` is truncated into 32-bit `CLST` bounds used as range guards in `attr_data_get_block()`, `attr_collapse_range()` and `attr_punch_hole()`, and inflates `sbi->mft.bitmap.nbits`, so attacker-chosen values defeat the bounds checks that keep cluster/MFT indexing in range and can expose kernel memory and out-of-range on-disk metadata.\nI:H - The same 64-bit-to-32-bit truncation and inflated MFT bitmap bounds let an attacker steer writes and MFT-extension arithmetic (`(u64)new_mft_total << record_bits`) outside the ranges the driver believes are valid, giving out-of-bounds indexing and filesystem-metadata corruption on a mounted read-write volume.\nA:H - The reported crash is a `WARN_ON_ONCE` splat from `kvmalloc_array()` in `wnd_init()` for an over-INT_MAX allocation, which is an immediate kernel panic on systems configured with `panic_on_warn`; tuned values instead force multi-hundred-megabyte to gigabyte kernel allocations and abort the mount, a reliable denial of service."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T11:42:43.308Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.1.131"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.6.60"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.11.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.12"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CVE Program Container","references":[{"url":"https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2025-11-03T19:31:42.870Z"}},{"affected":[{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.5","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.5","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.5","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.5","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIPLUS S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.5","status":"affected","lessThan":"*","versionType":"custom"}]}],"references":[{"url":"https://cert-portal.siemens.com/productcert/html/ssa-082556.html"}],"providerMetadata":{"shortName":"siemens-SADP","orgId":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e","dateUpdated":"2026-10-15T00:57:29.321Z"},"x_adpType":"supplier"}]}}}