140 lines
8.9 KiB
JSON
140 lines
8.9 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-2026-89664",
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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": "2026-09-11T19:38:34.745Z",
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"datePublished": "2026-09-11T19:45:51.319Z",
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"dateUpdated": "2026-10-19T08:50:35.770Z"
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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": "2026-10-19T08:50:35.770Z"
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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\nnfsd: release OPEN-decoded posix ACLs via op_release\n\nnfsd4_decode_createhow4() calls nfsd4_decode_fattr4(), which allocates\nrefcounted struct posix_acl objects via posix_acl_alloc() and stores\nthem in open->op_pacl and open->op_dpacl. These pointers must be\nreleased once the OPEN compound finishes.\n\nWhen nfsd4_decode_open_claim4() returns a non-seqid-mutating error,\nthe dispatcher short-circuits before op_func runs:\n\n nfsd4_proc_compound()\n if (op->status && op->opnum == OP_OPEN)\n op->status = nfsd4_open_omfg(...)\n if (!seqid_mutating_err(ntohl(op->status)))\n return op->status; /* nfsd4_open() never runs */\n ...\n opdesc->op_release(&op->u) /* must still release op_pacl/op_dpacl */\n\nBefore this change OP_OPEN had no .op_release in nfsd4_ops[], and the\nrelease pair lived inside nfsd4_open() at its out_err: label. On the\nshort-circuit path nfsd4_open() is never invoked, so both posix_acl\nrefs leak on every malformed OPEN compound that carries valid POSIX\nACL createhow4 attributes.\n\nAdd nfsd4_open_release() and wire it as .op_release for OP_OPEN.\nposix_acl_release() is NULL-safe, so the single release site covers\nboth the normal path and the nfsd4_open_omfg short-circuit. Remove\nthe matching posix_acl_release() pair from nfsd4_open()'s out_err:\nlabel to avoid double-releasing.\n\nThe compound loop has two encoding branches: nfsd4_encode_operation()\nfor normal ops, and nfsd4_encode_replay() for v4.0 replayed ops.\nop_release was only called from nfsd4_encode_operation(), so resources\nattached to op->u leak on the replay path.\n\nMove the op_release() call out of nfsd4_encode_operation() and the\nreplay branch, placing it after the if-else in nfsd4_proc_compound().\nThis gives a single call site in a fairly obviously-correct place,\ncovering both the normal encoding and replay paths."
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}
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],
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"metrics": [
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{
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"cvssV3_1": {
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"version": "3.1",
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"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
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"baseScore": 7.5,
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"baseSeverity": "HIGH"
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},
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"scenarios": [
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{
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"lang": "en",
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"value": "AV:N - The leak is in nfsd NFSv4 OPEN XDR decoding (nfsd4_decode_createhow4 → nfsd4_decode_fattr4 → posix_acl_alloc), reached over the network via COMPOUND RPCs on TCP/UDP port 2049 when the in-kernel NFS server is running.\nAC:L - An attacker can deterministically leak the ACLs by sending OPEN with CREATE and valid POSIX ACL attributes, then a non-seqid-mutating decode error such as NFS4ERR_BADXDR on open_claim4, so nfsd4_open() never runs; no race or luck is required.\nPR:N - OPEN decode allocates the posix_acl objects after spoofable RPC AUTH_UNIX and before nfsd4_open(), fh_verify(), export permission checks, or clientid/session validation, so no authenticated NFS identity or local account on the server is required.\nUI:N - The attacker triggers the leak solely by sending crafted NFSv4 COMPOUND packets; no victim user must mount a filesystem, open a file, or take any other action.\nS:U - Impact is confined to kernel slab consumption on the NFS server host and does not cross a VM, guest, sandbox, or IOMMU security boundary.\nC:N - This is a refcount leak of attacker-supplied posix_acl allocations with no out-of-bounds read, use-after-free, or other primitive that could disclose kernel or file data.\nI:N - The short-circuit path never runs nfsd4_open() or writes file/ACL metadata; the only effect is orphaned kmalloc objects, with no memory corruption or unauthorized modification.\nA:H - Each malformed OPEN permanently leaks up to two posix_acl objects (NFS_ACL_MAX_ENTRIES=1024, about 16KB each) for the server lifetime; repeating the request exhausts kernel memory and can OOM the NFS server and co-hosted workloads."
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}
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]
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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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"fs/nfsd/nfs4proc.c",
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"fs/nfsd/nfs4xdr.c"
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],
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"versions": [
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{
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"version": "5fc51dfc2eb160bd7ab3251ab1767cacf9c8bf05",
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"lessThan": "5b3a7d7c23c071efe12dd1bc1d2e5f97c4892921",
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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": "5fc51dfc2eb160bd7ab3251ab1767cacf9c8bf05",
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"lessThan": "8215892993ea9f5231da4fa9eb42428a286fce8b",
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"status": "affected",
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"versionType": "git"
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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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"fs/nfsd/nfs4proc.c",
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"fs/nfsd/nfs4xdr.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": "7.2.4",
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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": "7.2.4"
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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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}
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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/5b3a7d7c23c071efe12dd1bc1d2e5f97c4892921"
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},
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{
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"url": "https://git.kernel.org/stable/c/8215892993ea9f5231da4fa9eb42428a286fce8b"
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}
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],
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"title": "nfsd: release OPEN-decoded posix ACLs via op_release",
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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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} |