{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89672", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.746Z", "datePublished": "2026-09-11T19:45:57.414Z", "dateUpdated": "2026-10-19T08:50:45.617Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:50:45.617Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: gate nfs2 setacl by argp->mask\n\nThe NFSACL v2 SETACL path shares the decoder convention used by its\nv3 sibling: nfsaclsvc_decode_setaclargs() fills in argp->acl_access\nonly when NFS_ACL is set in the request mask and argp->acl_default\nonly when NFS_DFACL is set, leaving the other pointer NULL because\nthe argument buffer is zeroed up to pc_argzero before decode.\n\nnfsacld_proc_setacl() then hands both pointers to set_posix_acl()\nunconditionally. set_posix_acl(idmap, dentry, type, NULL) is the VFS\n\"remove this ACL type\" operation, so an omitted arm is\nindistinguishable from an explicit request to delete that ACL. A\nSETACL carrying only NFS_ACL silently strips the directory's default\nACL; mask=0 strips both.\n\nThis is the same defect just fixed in nfsd3_proc_setacl(); apply the\nsame remedy. Gate each set_posix_acl() call on its mask bit and\ninitialize error to 0 so that a request with neither bit set leaves\nthe on-disk ACLs untouched and returns success. The out_drop_lock\npath and the unconditional posix_acl_release() in\nnfsaclsvc_release_setacl() already tolerate the skipped arms." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N", "baseScore": 9.1, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - The flaw is in nfsd NFSACL v2 SETACL (RPC program 100227, ACLPROC2_SETACL) in nfsacld_proc_setacl(); a remote NFS client reaches it over TCP/UDP 2049 via svc_process to nfsd_dispatch and nfsaclsvc_decode_setaclargs.\nAC:L - The attacker supplies the SETACL mask and filehandle. A request with only NFS_ACL, only NFS_DFACL, or mask=0 leaves the omitted posix_acl pointer NULL (pc_argzero), and set_posix_acl() treats NULL as delete with no race or uninfluencable victim state.\nPR:N - Typical AUTH_SYS nfsd exports do not cryptographically verify RPC credentials; any host allowed by the export can MOUNT/LOOKUP and send SETACL with a spoofed AUTH_UNIX owner uid so nfsd_setuser() and inode_owner_or_capable() succeed without a local account.\nUI:N - The attacking NFS client sends the SETACL RPC itself; no local user or administrator action on the NFS server, such as mounting a filesystem or opening a file, is required at attack time.\nS:U - Unintended set_posix_acl(NULL) only removes POSIX ACL xattrs on the exported filesystem of the nfsd host; impact stays in that kernel/filesystem security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - Silently deleting a directory default ACL (SETACL with only NFS_ACL, or mask=0 stripping both) drops inheritance so new files are governed only by mode/umask, allowing a remote client to READ subsequently created data those default ACLs were meant to keep confidential.\nI:H - nfsacld_proc_setacl() calls set_posix_acl(..., NULL) for every ACL type omitted from the mask, which is the VFS delete operation, so an attacker-chosen inode can have its access ACL, default ACL, or both completely removed and later writes those ACLs would have denied.\nA:N - This is an unintended POSIX ACL deletion through the normal set_posix_acl(NULL) remove path; it does not oops, panic, hang, deadlock, or leak memory, so the NFS server and host remain available." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/nfsd/nfs2acl.c" ], "versions": [ { "version": "a257cdd0e2179630d3201c32ba14d7fcb3c3a055", "lessThan": "8e4422b05f410f95c51b68a0db4bf1d87f6d22f5", "status": "affected", "versionType": "git" }, { "version": "a257cdd0e2179630d3201c32ba14d7fcb3c3a055", "lessThan": "e41d173d9dc735cecb15ab7aa63ecab09338f81b", "status": "affected", "versionType": "git" }, { "version": "a257cdd0e2179630d3201c32ba14d7fcb3c3a055", "lessThan": "f951b22dbeec46f2e0fba81cb80d1b0c686b61eb", "status": "affected", "versionType": "git" }, { "version": "a257cdd0e2179630d3201c32ba14d7fcb3c3a055", "lessThan": "37eea38e7898538f0ec5f1eb8b18d8646e4be41c", "status": "affected", "versionType": "git" }, { "version": "a257cdd0e2179630d3201c32ba14d7fcb3c3a055", "lessThan": "a3a7e20ed66d3f04d37883c398da8a113b430769", "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/nfs2acl.c" ], "versions": [ { "version": "2.6.13", "status": "affected" }, { "version": "0", "lessThan": "2.6.13", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.109", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "2.6.13", "versionEndExcluding": "6.6.157" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.13", "versionEndExcluding": "6.12.109" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.13", "versionEndExcluding": "6.18.50" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.13", "versionEndExcluding": "7.2.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.13", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/8e4422b05f410f95c51b68a0db4bf1d87f6d22f5" }, { "url": "https://git.kernel.org/stable/c/e41d173d9dc735cecb15ab7aa63ecab09338f81b" }, { "url": "https://git.kernel.org/stable/c/f951b22dbeec46f2e0fba81cb80d1b0c686b61eb" }, { "url": "https://git.kernel.org/stable/c/37eea38e7898538f0ec5f1eb8b18d8646e4be41c" }, { "url": "https://git.kernel.org/stable/c/a3a7e20ed66d3f04d37883c398da8a113b430769" } ], "title": "nfsd: gate nfs2 setacl by argp->mask", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2026-89672", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "yes" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2026-10-16T19:25:46.874632Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:26:48.206Z" } } ] } }