{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2023-52909", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-08-21T06:07:11.015Z", "datePublished": "2024-08-21T06:10:50.303Z", "dateUpdated": "2026-08-05T09:11:55.987Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T09:11:55.987Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix handling of cached open files in nfsd4_open codepath\n\nCommit fb70bf124b05 (\"NFSD: Instantiate a struct file when creating a\nregular NFSv4 file\") added the ability to cache an open fd over a\ncompound. There are a couple of problems with the way this currently\nworks:\n\nIt's racy, as a newly-created nfsd_file can end up with its PENDING bit\ncleared while the nf is hashed, and the nf_file pointer is still zeroed\nout. Other tasks can find it in this state and they expect to see a\nvalid nf_file, and can oops if nf_file is NULL.\n\nAlso, there is no guarantee that we'll end up creating a new nfsd_file\nif one is already in the hash. If an extant entry is in the hash with a\nvalid nf_file, nfs4_get_vfs_file will clobber its nf_file pointer with\nthe value of op_file and the old nf_file will leak.\n\nFix both issues by making a new nfsd_file_acquirei_opened variant that\ntakes an optional file pointer. If one is present when this is called,\nwe'll take a new reference to it instead of trying to open the file. If\nthe nfsd_file already has a valid nf_file, we'll just ignore the\noptional file and pass the nfsd_file back as-is.\n\nAlso rework the tracepoints a bit to allow for an \"opened\" variant and\ndon't try to avoid counting acquisitions in the case where we already\nhave a cached open file." } ], "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 OPEN/CREATE path (nfsd4_open → nfs4_get_vfs_file → nfsd_file_create) on the in-kernel NFS server, reachable over the network via RPC to nfsd.\nAC:L - The race is between clearing NFSD_FILE_PENDING with nf_file still NULL and the later assignment of op_filp; an attacker can drive both sides with concurrent OPEN(CREATE)/OPEN requests for the same file and credentials.\nPR:N - Typical nfsd deployments use AUTH_SYS/AUTH_NULL with IP-based exports, so a remote peer that can reach the export can establish a clientid and trigger OPEN without real authentication.\nUI:N - Exploitation requires only attacker-sent NFS compounds; no victim user action is needed.\nS:U - Impact is confined to the NFS server kernel (oops/DoS or a struct file leak); it does not cross a separate security authority such as a VM or IOMMU boundary.\nC:N - The primary failure is a NULL pointer dereference of nf_file leading to an oops; there is no information disclosure or UAF read primitive.\nI:N - The bug causes a crash and a possible nf_file pointer leak/clobber without freeing the old file, not a write primitive or control-flow hijack.\nA:H - Concurrent lookups can call file_inode(nf->nf_file) while nf_file is still NULL, causing a kernel oops and denial of service of the NFS server." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/nfsd/filecache.c", "fs/nfsd/filecache.h", "fs/nfsd/nfs4state.c", "fs/nfsd/trace.h" ], "versions": [ { "version": "c20097329d2c196b818c4666c7820c1378d69d61", "lessThan": "45c08a752982116f3287afcd1bd9c50f4fab0c28", "status": "affected", "versionType": "git" }, { "version": "106331a12b0fa5afa6995b1f9ebb03ddcaac6915", "lessThan": "0b778361998d6c6356b8d2fc7ddf025fb3224654", "status": "affected", "versionType": "git" }, { "version": "fb70bf124b051d4ded4ce57511dfec6d3ebf2b43", "lessThan": "973acfdfe90c8a4e58ade97ff0653a498531ff2e", "status": "affected", "versionType": "git" }, { "version": "fb70bf124b051d4ded4ce57511dfec6d3ebf2b43", "lessThan": "0b3a551fa58b4da941efeb209b3770868e2eddd7", "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/nfsd/filecache.c", "fs/nfsd/filecache.h", "fs/nfsd/nfs4state.c", "fs/nfsd/trace.h" ], "versions": [ { "version": "5.19", "status": "affected" }, { "version": "0", "lessThan": "5.19", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.7", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.2", "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": "5.19", "versionEndExcluding": "6.1.7" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/45c08a752982116f3287afcd1bd9c50f4fab0c28" }, { "url": "https://git.kernel.org/stable/c/0b778361998d6c6356b8d2fc7ddf025fb3224654" }, { "url": "https://git.kernel.org/stable/c/973acfdfe90c8a4e58ade97ff0653a498531ff2e" }, { "url": "https://git.kernel.org/stable/c/0b3a551fa58b4da941efeb209b3770868e2eddd7" } ], "title": "nfsd: fix handling of cached open files in nfsd4_open codepath", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2023-52909", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2024-09-10T16:03:02.157963Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-09-12T17:33:12.921Z" } } ] } }