Linux Kernel NFSd POSIX ACL Leak on SETACL Decode Failure
CVE-2026-53397 Published on July 19, 2026
nfsd: fix posix_acl leak on SETACL decode failure
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.
Products Associated with CVE-2026-53397
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Affected Versions
Linux:- Version a257cdd0e2179630d3201c32ba14d7fcb3c3a055 and below b2eb1ffd511d1b3c3e21122f97cbbccea411e277 is affected.
- Version a257cdd0e2179630d3201c32ba14d7fcb3c3a055 and below b94c4be77682aab06d65ca7296149e3bcfb37353 is affected.
- Version a257cdd0e2179630d3201c32ba14d7fcb3c3a055 and below 887f92ceccf3eacd5f2402db21254d66372fae00 is affected.
- Version a257cdd0e2179630d3201c32ba14d7fcb3c3a055 and below 1e96239fddcefacf6afe6c498357be68eacbcabc is affected.
- Version a257cdd0e2179630d3201c32ba14d7fcb3c3a055 and below bd69a825485168ef74e815ecb286754b570fdcc7 is affected.
- Version a257cdd0e2179630d3201c32ba14d7fcb3c3a055 and below 136b416593f1349cf6f72c8e3d18f0f204ee8545 is affected.
- Version a257cdd0e2179630d3201c32ba14d7fcb3c3a055 and below a5b42c1e4ff2befaa6b96f7cbf32174751eba083 is affected.
- Version a257cdd0e2179630d3201c32ba14d7fcb3c3a055 and below 0853ac544c590880d797b04daa33fcb72b6be0e1 is affected.
- Version 2.6.13 is affected.
- Before 2.6.13 is unaffected.
- Version 5.10.260, <= 5.10.* is unaffected.
- Version 5.15.211, <= 5.15.* is unaffected.
- Version 6.1.177, <= 6.1.* is unaffected.
- Version 6.6.144, <= 6.6.* is unaffected.
- Version 6.12.95, <= 6.12.* is unaffected.
- Version 6.18.38, <= 6.18.* is unaffected.
- Version 7.1.3, <= 7.1.* is unaffected.
- Version 7.2, <= * is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.