CVE-2026-89672
Received
Received - Intake
Linux kernel NFSACL v2 SETACL Privilege Escalation
Vulnerability report for CVE-2026-89672, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-09-11
Last updated on: 2026-09-11
Assigner: kernel.org
Description
Description
In the Linux kernel, the following vulnerability has been resolved:
nfsd: gate nfs2 setacl by argp->mask
The NFSACL v2 SETACL path shares the decoder convention used by its
v3 sibling: nfsaclsvc_decode_setaclargs() fills in argp->acl_access
only when NFS_ACL is set in the request mask and argp->acl_default
only when NFS_DFACL is set, leaving the other pointer NULL because
the argument buffer is zeroed up to pc_argzero before decode.
nfsacld_proc_setacl() then hands both pointers to set_posix_acl()
unconditionally. set_posix_acl(idmap, dentry, type, NULL) is the VFS
"remove this ACL type" operation, so an omitted arm is
indistinguishable from an explicit request to delete that ACL. A
SETACL carrying only NFS_ACL silently strips the directory's default
ACL; mask=0 strips both.
This is the same defect just fixed in nfsd3_proc_setacl(); apply the
same remedy. Gate each set_posix_acl() call on its mask bit and
initialize error to 0 so that a request with neither bit set leaves
the on-disk ACLs untouched and returns success. The out_drop_lock
path and the unconditional posix_acl_release() in
nfsaclsvc_release_setacl() already tolerate the skipped arms.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | * |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
