{"id":"CVE-2026-53397","state":"PUBLISHED","title":"nfsd: fix posix_acl leak on SETACL decode failure","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix posix_acl leak on SETACL decode failure\n\nnfsaclsvc_decode_setaclargs() and nfs3svc_decode_setaclargs() each\ncall nfs_stream_decode_acl() twice, first for NFS_ACL and then for\nNFS_DFACL.  Each successful call transfers ownership of a freshly\nallocated posix_acl into argp->acl_access or argp->acl_default.  If\nthe first call succeeds but the second fails, the decoder returns\nfalse and argp->acl_access is left dangling.\n\nACLPROC2_SETACL.pc_release was wired to nfssvc_release_attrstat and\nACLPROC3_SETACL.pc_release was wired to nfs3svc_release_fhandle.\nBoth only call fh_put() and have no knowledge of the ACL fields on\nargp.  The posix_acl_release() pairs sat at the out: labels inside\nnfsacld_proc_setacl() and nfsd3_proc_setacl(), but svc_process()\nskips pc_func when pc_decode returns false, so that cleanup is\nunreachable on decode failure:\n\n    svc_process_common()\n      pc_decode()                  /* decode_setaclargs: false */\n      /* pc_func skipped */\n      pc_release()                 /* fh_put only -- ACLs leaked */\n\nThe orphaned posix_acl is leaked for the lifetime of the server.\n\nFix by adding nfsaclsvc_release_setacl() and nfs3svc_release_setacl(),\nwhich release both argp->acl_access and argp->acl_default in addition\nto fh_put(), and wiring them as pc_release for their respective SETACL\nprocedures.  pc_release runs on every path svc_process() takes after\ndecode, including decode failure, so the posix_acl_release() pairs are\nremoved from the proc functions' out: labels to keep ownership in one\nplace.  This matches the existing release_getacl() pattern used by\nthe sibling GETACL procedures.","publishedAt":"2026-07-19T12:01:58.938Z","updatedAt":"2026-10-19T20:07:46.415Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","status":"affected","lessThan":"b2eb1ffd511d1b3c3e21122f97cbbccea411e277","versionType":"git"},{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","status":"affected","lessThan":"b94c4be77682aab06d65ca7296149e3bcfb37353","versionType":"git"},{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","status":"affected","lessThan":"887f92ceccf3eacd5f2402db21254d66372fae00","versionType":"git"},{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","status":"affected","lessThan":"1e96239fddcefacf6afe6c498357be68eacbcabc","versionType":"git"},{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","status":"affected","lessThan":"bd69a825485168ef74e815ecb286754b570fdcc7","versionType":"git"},{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","status":"affected","lessThan":"136b416593f1349cf6f72c8e3d18f0f204ee8545","versionType":"git"},{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","status":"affected","lessThan":"a5b42c1e4ff2befaa6b96f7cbf32174751eba083","versionType":"git"},{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","status":"affected","lessThan":"0853ac544c590880d797b04daa33fcb72b6be0e1","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfsd/nfs2acl.c","fs/nfsd/nfs3acl.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.13","versionType":"semver"},{"version":"5.10.260","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.211","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.177","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.144","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.95","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.38","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.3","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfsd/nfs2acl.c","fs/nfsd/nfs3acl.c"]}],"references":["https://git.kernel.org/stable/c/b2eb1ffd511d1b3c3e21122f97cbbccea411e277","https://git.kernel.org/stable/c/b94c4be77682aab06d65ca7296149e3bcfb37353","https://git.kernel.org/stable/c/887f92ceccf3eacd5f2402db21254d66372fae00","https://git.kernel.org/stable/c/1e96239fddcefacf6afe6c498357be68eacbcabc","https://git.kernel.org/stable/c/bd69a825485168ef74e815ecb286754b570fdcc7","https://git.kernel.org/stable/c/136b416593f1349cf6f72c8e3d18f0f204ee8545","https://git.kernel.org/stable/c/a5b42c1e4ff2befaa6b96f7cbf32174751eba083","https://git.kernel.org/stable/c/0853ac544c590880d797b04daa33fcb72b6be0e1"],"weaknesses":["CWE-401"],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/53xxx/CVE-2026-53397.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53397","state":"PUBLISHED","datePublished":"2026-07-19T12:01:58.938Z","dateUpdated":"2026-10-19T20:07:46.415Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-06-09T07:44:35.402Z"},"containers":{"cna":{"title":"nfsd: fix posix_acl leak on SETACL decode failure","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix posix_acl leak on SETACL decode failure\n\nnfsaclsvc_decode_setaclargs() and nfs3svc_decode_setaclargs() each\ncall nfs_stream_decode_acl() twice, first for NFS_ACL and then for\nNFS_DFACL.  Each successful call transfers ownership of a freshly\nallocated posix_acl into argp->acl_access or argp->acl_default.  If\nthe first call succeeds but the second fails, the decoder returns\nfalse and argp->acl_access is left dangling.\n\nACLPROC2_SETACL.pc_release was wired to nfssvc_release_attrstat and\nACLPROC3_SETACL.pc_release was wired to nfs3svc_release_fhandle.\nBoth only call fh_put() and have no knowledge of the ACL fields on\nargp.  The posix_acl_release() pairs sat at the out: labels inside\nnfsacld_proc_setacl() and nfsd3_proc_setacl(), but svc_process()\nskips pc_func when pc_decode returns false, so that cleanup is\nunreachable on decode failure:\n\n    svc_process_common()\n      pc_decode()                  /* decode_setaclargs: false */\n      /* pc_func skipped */\n      pc_release()                 /* fh_put only -- ACLs leaked */\n\nThe orphaned posix_acl is leaked for the lifetime of the server.\n\nFix by adding nfsaclsvc_release_setacl() and nfs3svc_release_setacl(),\nwhich release both argp->acl_access and argp->acl_default in addition\nto fh_put(), and wiring them as pc_release for their respective SETACL\nprocedures.  pc_release runs on every path svc_process() takes after\ndecode, including decode failure, so the posix_acl_release() pairs are\nremoved from the proc functions' out: labels to keep ownership in one\nplace.  This matches the existing release_getacl() pattern used by\nthe sibling GETACL procedures."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","status":"affected","lessThan":"b2eb1ffd511d1b3c3e21122f97cbbccea411e277","versionType":"git"},{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","status":"affected","lessThan":"b94c4be77682aab06d65ca7296149e3bcfb37353","versionType":"git"},{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","status":"affected","lessThan":"887f92ceccf3eacd5f2402db21254d66372fae00","versionType":"git"},{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","status":"affected","lessThan":"1e96239fddcefacf6afe6c498357be68eacbcabc","versionType":"git"},{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","status":"affected","lessThan":"bd69a825485168ef74e815ecb286754b570fdcc7","versionType":"git"},{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","status":"affected","lessThan":"136b416593f1349cf6f72c8e3d18f0f204ee8545","versionType":"git"},{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","status":"affected","lessThan":"a5b42c1e4ff2befaa6b96f7cbf32174751eba083","versionType":"git"},{"version":"a257cdd0e2179630d3201c32ba14d7fcb3c3a055","status":"affected","lessThan":"0853ac544c590880d797b04daa33fcb72b6be0e1","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfsd/nfs2acl.c","fs/nfsd/nfs3acl.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.13","versionType":"semver"},{"version":"5.10.260","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.211","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.177","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.144","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.95","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.38","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.3","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfsd/nfs2acl.c","fs/nfsd/nfs3acl.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/b2eb1ffd511d1b3c3e21122f97cbbccea411e277"},{"url":"https://git.kernel.org/stable/c/b94c4be77682aab06d65ca7296149e3bcfb37353"},{"url":"https://git.kernel.org/stable/c/887f92ceccf3eacd5f2402db21254d66372fae00"},{"url":"https://git.kernel.org/stable/c/1e96239fddcefacf6afe6c498357be68eacbcabc"},{"url":"https://git.kernel.org/stable/c/bd69a825485168ef74e815ecb286754b570fdcc7"},{"url":"https://git.kernel.org/stable/c/136b416593f1349cf6f72c8e3d18f0f204ee8545"},{"url":"https://git.kernel.org/stable/c/a5b42c1e4ff2befaa6b96f7cbf32174751eba083"},{"url":"https://git.kernel.org/stable/c/0853ac544c590880d797b04daa33fcb72b6be0e1"}],"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 vulnerable code is in nfsd's NFS ACL program (RPC program 100227), reachable over the network via the in-kernel NFS server on TCP/UDP port 2049 when NFSD ACL support is enabled.\nAC:L - Once nfsd with ACL support is running, an attacker can reliably trigger the leak by sending a SETACL RPC with mask including both NFS_ACL and NFS_DFACL, a valid first ACL, and a malformed second ACL that fails decode.\nPR:N - Exploitation requires only network access as an NFS client with RPC credentials (AUTH_UNIX is spoofable) from a source IP matching an export entry; no local shell or real root on the server is needed.\nUI:N - Triggering the leak requires only crafted NFS ACL RPC packets; no victim user action such as mounting a filesystem or opening a file is required.\nS:U - The impact is confined to kernel memory consumption within the nfsd server context and does not cross a security boundary such as a VM, container, or IOMMU isolation boundary.\nC:N - This is a kmalloc leak of attacker-supplied ACL data with no out-of-bounds read, use-after-free, or other mechanism that exposes kernel memory to the attacker.\nI:N - The bug orphans allocated posix_acl objects without modifying file data, ACLs on disk, or any other integrity-protected resources.\nA:H - Each trigger permanently leaks a posix_acl allocation (up to ~16KB with max entries) for the server's lifetime; repeated remote SETACL requests can exhaust kernel memory and deny service to the NFS server and co-hosted workloads."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T04:50:49.240Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"5.10.260"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"5.15.211"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"6.1.177"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"6.6.144"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"6.12.95"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"6.18.38"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"7.1.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-53397","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T15:30:22.806921Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-401","lang":"en","type":"CWE","description":"CWE-401 Missing Release of Memory after Effective Lifetime"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T20:07:46.415Z"}}]}}}