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.
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:

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

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.

References

• https://nvd.nist.gov/vuln/detail/CVE-2026-53397
• https://git.kernel.org/stable/c/0853ac544c590880d797b04daa33fcb72b6be0e1
• https://git.kernel.org/stable/c/136b416593f1349cf6f72c8e3d18f0f204ee8545
• https://git.kernel.org/stable/c/1e96239fddcefacf6afe6c498357be68eacbcabc
• https://git.kernel.org/stable/c/887f92ceccf3eacd5f2402db21254d66372fae00
• https://git.kernel.org/stable/c/a5b42c1e4ff2befaa6b96f7cbf32174751eba083
• https://git.kernel.org/stable/c/b2eb1ffd511d1b3c3e21122f97cbbccea411e277
• https://git.kernel.org/stable/c/b94c4be77682aab06d65ca7296149e3bcfb37353
• https://git.kernel.org/stable/c/bd69a825485168ef74e815ecb286754b570fdcc7