Misinterpretation of Input Affecting perf6.18-debuginfo package, versions <1:6.18.51-120.162.amzn2023


Severity

Recommended
0.0
high
0
10

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.5% (41st percentile)

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  • Snyk IDSNYK-AMZN2023-PERF618DEBUGINFO-20854486
  • published13 Oct 2026
  • disclosed11 Sept 2026

Introduced: 11 Sep 2026

CVE-2026-89671  (opens in a new tab)
CWE-115  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 perf6.18-debuginfo to version 1:6.18.51-120.162.amzn2023 or higher.
This issue was patched in ALAS2023-2026-3187.

NVD Description

Note: Versions mentioned in the description apply only to the upstream perf6.18-debuginfo package and not the perf6.18-debuginfo package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

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

nfsd: gate nfs3 setacl by argp->mask

nfsd3_proc_setacl() calls set_posix_acl() unconditionally for both ACL_TYPE_ACCESS and ACL_TYPE_DEFAULT, passing argp->acl_access and argp->acl_default verbatim. The NFSv3 ACL decoder only populates those pointers when the corresponding mask bit is set:

nfs3svc_decode_setaclargs()
  if (args-&gt;mask &amp; NFS_ACL)    decode into acl_access
  if (args-&gt;mask &amp; NFS_DFACL)  decode into acl_default
  /* otherwise the pointer stays NULL (pc_argzero) */

nfsd3_proc_setacl() set_posix_acl(.., ACL_TYPE_ACCESS, argp-&gt;acl_access) set_posix_acl(.., ACL_TYPE_DEFAULT, argp-&gt;acl_default)

set_posix_acl(idmap, dentry, type, NULL) is the VFS "remove this ACL type" operation. A NULL pointer that means "the client did not send this arm" is therefore indistinguishable from "the client asked to remove this ACL". A SETACL with mask=NFS_ACL silently drops the directory's default ACL; mask=0 drops both.

The sibling nfsd3_proc_getacl() already consults argp->mask before touching each arm; mirror that in setacl.

Fix by wrapping each set_posix_acl() call in the matching mask bit check and initializing error to 0 before inode_lock so that a request with neither bit set leaves the on-disk ACLs untouched and returns nfs_ok. The out_drop_lock path and the unconditional posix_acl_release() at out: are preserved; both NULL-tolerate the skipped arms.

CVSS Base Scores

version 3.1