CVE-2026-53397

Estado: AnalizadaAlta (7.5)—

In the Linux kernel, the following vulnerability has been resolved:

nfsd: fix posix_acl leak on SETACL decode failure

nfsaclsvc_decode_setaclargs() and nfs3svc_decode_setaclargs() each call nfs_stream_decode_acl() twice, first for NFS_ACL and then for NFS_DFACL. Each successful call transfers ownership of a freshly allocated posix_acl into argp->acl_access or argp->acl_default. If the first call succeeds but the second fails, the decoder returns false and argp->acl_access is left dangling.

ACLPROC2_SETACL.pc_release was wired to nfssvc_release_attrstat and ACLPROC3_SETACL.pc_release was wired to nfs3svc_release_fhandle.

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Both only call fh_put() and have no knowledge of the ACL fields on argp. The posix_acl_release() pairs sat at the out: labels inside nfsacld_proc_setacl() and nfsd3_proc_setacl(), but svc_process() skips pc_func when pc_decode returns false, so that cleanup is unreachable on decode failure:

The orphaned posix_acl is leaked for the lifetime of the server.

Fix by adding nfsaclsvc_release_setacl() and nfs3svc_release_setacl(), which release both argp->acl_access and argp->acl_default in addition to fh_put(), and wiring them as pc_release for their respective SETACL procedures. pc_release runs on every path svc_process() takes after decode, including decode failure, so the posix_acl_release() pairs are removed from the proc functions' out: labels to keep ownership in one place. This matches the existing release_getacl() pattern used by the sibling GETACL procedures.

Detalles técnicos trazas, registros y código del informe original

    svc_process_common()
      pc_decode()                  /* decode_setaclargs: false */
      /* pc_func skipped */
      pc_release()                 /* fh_put only -- ACLs leaked */

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Puntuación base: 7.5

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.53%
Percentil entre todas las CVEs puntuadas: 43
Fecha de la puntuación: 3/10/2026

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access60 %
Impacto principalT1499 Endpoint Denial of Serviceimpact55 %

Inferido por reglas deterministas a partir del vector CVSS y la CWE. Solo orientativo.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Filter Network Traffic Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Application Isolation and Sandboxing

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-401

Referencias

JSON original (NVD)

Mostrar

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      "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."
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