180 lines
10 KiB
JSON
180 lines
10 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-2026-89691",
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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": "2026-09-11T19:38:34.749Z",
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"datePublished": "2026-09-11T19:46:11.284Z",
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"dateUpdated": "2026-10-19T08:51:04.497Z"
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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": "2026-10-19T08:51:04.497Z"
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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: clear opcnt on compound arg release to prevent OOB read\n\nnfsd4_release_compoundargs() resets args->ops to the inline iops[8]\narray when the dynamically-allocated ops buffer is freed, but leaves\nargs->opcnt at its original value (which can be up to 200 for NFSv4.1+\ncompounds).\n\nIf rq_status_counter is stuck at an odd value (which can happen when\nnfsd_dispatch() hits an error path after setting it odd), the RPC\nstatus dumpit handler reads min(opcnt, 16) entries from args->ops[].\nSince iops only has 8 elements and is the last field in struct\nnfsd4_compoundargs, reading indices 8-15 accesses adjacent slab memory\nand leaks it to userspace via netlink.\n\nZero opcnt unconditionally in nfsd4_release_compoundargs() so stale\ncompound metadata is never exposed through the status interface.\n\n[ cel: Remove the kvfree_rcu_mightsleep() sleep from the exposure window ]"
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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:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
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"baseScore": 7.1,
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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:L - The out-of-bounds read is in nfsd_nl_rpc_status_get_dumpit(), reached only via NFSD_CMD_RPC_STATUS_GET over AF_NETLINK. Remote NFSv4 compounds can leave stale opcnt after nfsd4_release_compoundargs() but never enter dumpit, so exploitation requires local netlink access.\nAC:L - The attacker can send an NFSv4.0 COMPOUND with more than eight ops including OP_CACHEME SETCLIENTID, then a duplicate in-flight RPC so nfsd_cache_lookup() returns RC_DROPIT and leaves rq_status_counter odd. Dumpit then deterministically reads min(opcnt,16) slots from the eight-element iops array; both sides are attacker-controlled.\nPR:L - NFSD_CMD_RPC_STATUS_GET is registered with GENL_CMD_CAP_DUMP and no GENL_ADMIN_PERM, so any unprivileged process in the nfsd network namespace can invoke the dump. Exploitation does not require CAP_NET_ADMIN or init-namespace root.\nUI:N - The attacker issues the netlink dump and the NFSv4 compounds themselves. No separate victim action such as mounting a filesystem or opening a device is required.\nS:U - The slab over-read and netlink leak occur in host-kernel nfsd on the local machine. Impact stays inside one security authority and is not a VM escape, IOMMU bypass, or other cross-boundary breakout.\nC:H - After release, dumpit reads args->ops[8..15].opnum past the trailing iops[8] array in nfsd4_compoundargs and returns those eight u32s via NFSD_A_RPC_STATUS_COMPOUND_OPS. That adjacent-slab out-of-bounds read is Confidentiality High unless limited to a few bytes.\nI:N - dumpit only loads opnum into a stack nfsd_genl_rqstp for netlink. There is no out-of-bounds write, use-after-free, or control-flow hijack primitive.\nA:H - Slots 8-15 are sampled at sizeof(struct nfsd4_op) stride past the kmalloc'd nfsd4_compoundargs object into adjacent or unmapped slab pages, which can oops the dumpit path even if the leak is not turned into a stable read."
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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/nfs4xdr.c"
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],
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"versions": [
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{
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"version": "bd9d6a3efa9709e653aafbeb859289feccb8e70c",
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"lessThan": "58bcdfb2b2e412088839ae740b1a95154dc0b8d0",
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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": "bd9d6a3efa9709e653aafbeb859289feccb8e70c",
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"lessThan": "e879148867bd4c4cac42e063ffaffa187dddc6fe",
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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": "bd9d6a3efa9709e653aafbeb859289feccb8e70c",
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"lessThan": "c1a4f7b1848f95302df598217e1c7a1410c2d0c5",
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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": "bd9d6a3efa9709e653aafbeb859289feccb8e70c",
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"lessThan": "ae4c38555e81563b8dc5eae55ffd70f0ea97aa5a",
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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/nfs4xdr.c"
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],
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"versions": [
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{
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"version": "6.7",
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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": "6.7",
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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": "6.12.109",
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"lessThanOrEqual": "6.12.*",
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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": "6.18.50",
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"lessThanOrEqual": "6.18.*",
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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": "6.7",
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"versionEndExcluding": "6.12.109"
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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": "6.7",
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"versionEndExcluding": "6.18.50"
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},
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "6.7",
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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": "6.7",
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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/58bcdfb2b2e412088839ae740b1a95154dc0b8d0"
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},
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{
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"url": "https://git.kernel.org/stable/c/e879148867bd4c4cac42e063ffaffa187dddc6fe"
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},
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{
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"url": "https://git.kernel.org/stable/c/c1a4f7b1848f95302df598217e1c7a1410c2d0c5"
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},
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{
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"url": "https://git.kernel.org/stable/c/ae4c38555e81563b8dc5eae55ffd70f0ea97aa5a"
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}
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],
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"title": "nfsd: clear opcnt on compound arg release to prevent OOB read",
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"x_generator": {
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} |