{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-53392", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-06-09T07:44:35.402Z", "datePublished": "2026-07-19T12:01:56.101Z", "dateUpdated": "2026-08-17T04:50:43.747Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:50:43.747Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSv4/flexfiles: reject zero filehandle version count\n\nff_layout_alloc_lseg() decodes the filehandle-version array count\nfrom the flexfiles layout body. The value is used as the count for\nkzalloc_objs(), and the current code only rejects NULL.\n\nA zero count yields ZERO_SIZE_PTR, which can be stored in\ndss_info->fh_versions even though later flexfiles paths assume that at\nleast one filehandle version exists.\n\nReject fh_count == 0 before the allocation, matching the existing zero\nversion_count validation in the flexfiles GETDEVICEINFO parser.\n\nA QEMU/KASAN run with a malformed flexfiles layout hit:\n\n KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]\n RIP: 0010:ff_layout_encode_ff_layoutupdate.isra.0+0x15f/0x750\n ff_layout_encode_layoutreturn+0x683/0x970\n nfs4_xdr_enc_layoutreturn+0x278/0x3a0\n Kernel panic - not syncing: Fatal exception\n\nThe patched kernel rejects the malformed layout without KASAN/oops/panic,\nand a valid fh_count=1 regression still opens, reads, and unmounts cleanly." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - The bug is in the NFSv4 pNFS flexfiles client parsing a malicious LAYOUTGET layout blob from the server over NFS/RPC; a remote attacker who controls or MITMs the NFS server delivers the crafted fh_count=0 response over the network.\nAC:L - Once a client is using flexfiles pNFS, the attacker fully controls the layout XDR and can set fh_count=0 to deterministically store ZERO_SIZE_PTR; a later I/O, layoutstats, or LAYOUTRETURN path dereferences fh_versions[0] and panics without races or special heap layout.\nPR:N - Exploitation requires no privileges on the victim host; the attacker only needs to be the (or impersonate) the NFS server sending protocol responses after normal client connection/authentication.\nUI:N - After an NFS pNFS flexfiles mount is established (common in enterprise/HPC NAS deployments), triggering the malformed layout and subsequent kernel panic requires no further victim action beyond routine file access on the already-mounted share.\nS:U - Impact is a kernel oops/panic on the NFS client host; it does not cross a VM, container, or IOMMU security boundary to affect a different authority.\nC:N - The failure mode is a NULL-pointer dereference at ZERO_SIZE_PTR (0x10) when accessing fh_versions[0]; KASAN confirms a faulting dereference with no successful out-of-bounds read or information leak to userspace.\nI:N - There is no memory corruption or successful write primitive—only an invalid-pointer dereference that crashes the kernel before any integrity-changing operation completes.\nA:H - A confirmed KASAN null-ptr-deref in ff_layout_encode_ff_layoutupdate during LAYOUTRETURN encoding causes a fatal kernel exception/panic, fully denying availability of the client system." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/nfs/flexfilelayout/flexfilelayout.c" ], "versions": [ { "version": "d67ae825a59d639e4d8b82413af84d854617a87e", "lessThan": "9033591535c066726f5b505126ccb4068b98fa4f", "status": "affected", "versionType": "git" }, { "version": "d67ae825a59d639e4d8b82413af84d854617a87e", "lessThan": "18cc6d57a14fa65ab2a2b52279f549041c4bc9cf", "status": "affected", "versionType": "git" }, { "version": "d67ae825a59d639e4d8b82413af84d854617a87e", "lessThan": "be7829715e341b42846437dd9e721005db59f0cc", "status": "affected", "versionType": "git" }, { "version": "d67ae825a59d639e4d8b82413af84d854617a87e", "lessThan": "eeabb9020721db6bc132e68eeae380b8d4fb4b04", "status": "affected", "versionType": "git" }, { "version": "d67ae825a59d639e4d8b82413af84d854617a87e", "lessThan": "7779c85028a0676fb190cde4f0c540f4f8e97761", "status": "affected", "versionType": "git" }, { "version": "d67ae825a59d639e4d8b82413af84d854617a87e", "lessThan": "d8c90c7cc061265d5f2813a1f5c82ef2f4707e67", "status": "affected", "versionType": "git" }, { "version": "d67ae825a59d639e4d8b82413af84d854617a87e", "lessThan": "2131ed64b767ffa8bcdb3677d90f3964e39aabc8", "status": "affected", "versionType": "git" }, { "version": "d67ae825a59d639e4d8b82413af84d854617a87e", "lessThan": "2c6bb3c40bc24f6aa8dfbe6fe98c3ad6389203f2", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/nfs/flexfilelayout/flexfilelayout.c" ], "versions": [ { "version": "4.0", "status": "affected" }, { "version": "0", "lessThan": "4.0", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.261", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.212", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.96", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.38", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.3", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "4.0", "versionEndExcluding": "5.10.261" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.0", "versionEndExcluding": "5.15.212" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.0", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.0", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.0", "versionEndExcluding": "6.12.96" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.0", "versionEndExcluding": "6.18.38" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.0", "versionEndExcluding": "7.1.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.0", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/9033591535c066726f5b505126ccb4068b98fa4f" }, { "url": "https://git.kernel.org/stable/c/18cc6d57a14fa65ab2a2b52279f549041c4bc9cf" }, { "url": "https://git.kernel.org/stable/c/be7829715e341b42846437dd9e721005db59f0cc" }, { "url": "https://git.kernel.org/stable/c/eeabb9020721db6bc132e68eeae380b8d4fb4b04" }, { "url": "https://git.kernel.org/stable/c/7779c85028a0676fb190cde4f0c540f4f8e97761" }, { "url": "https://git.kernel.org/stable/c/d8c90c7cc061265d5f2813a1f5c82ef2f4707e67" }, { "url": "https://git.kernel.org/stable/c/2131ed64b767ffa8bcdb3677d90f3964e39aabc8" }, { "url": "https://git.kernel.org/stable/c/2c6bb3c40bc24f6aa8dfbe6fe98c3ad6389203f2" } ], "title": "NFSv4/flexfiles: reject zero filehandle version count", "x_generator": { "engine": "bippy-1.2.0" } } } }