CVE-2026-53397
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.53%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.53% probability · 43th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-401
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/0853ac544c590880d797b04daa33fcb72b6be0e1Patch
- https://git.kernel.org/stable/c/136b416593f1349cf6f72c8e3d18f0f204ee8545Patch
- https://git.kernel.org/stable/c/1e96239fddcefacf6afe6c498357be68eacbcabcPatch
- https://git.kernel.org/stable/c/887f92ceccf3eacd5f2402db21254d66372fae00Patch
- https://git.kernel.org/stable/c/a5b42c1e4ff2befaa6b96f7cbf32174751eba083Patch
- https://git.kernel.org/stable/c/b2eb1ffd511d1b3c3e21122f97cbbccea411e277Patch
- https://git.kernel.org/stable/c/b94c4be77682aab06d65ca7296149e3bcfb37353Patch
- https://git.kernel.org/stable/c/bd69a825485168ef74e815ecb286754b570fdcc7Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.