CVE-2026-31709 Affecting kernel-debug-modules-extra package, versions <0:5.14.0-687.12.1.el9_8


Severity

Recommended
high

Based on Rocky Linux security rating.

Threat Intelligence

EPSS
0.05% (16th percentile)

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  • Snyk IDSNYK-ROCKY9-KERNELDEBUGMODULESEXTRA-17110161
  • published31 May 2026
  • disclosed1 May 2026

Introduced: 1 May 2026

NewCVE-2026-31709  (opens in a new tab)

How to fix?

Upgrade Rocky-Linux:9 kernel-debug-modules-extra to version 0:5.14.0-687.12.1.el9_8 or higher.
This issue was patched in RLSA-2026:21556.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-debug-modules-extra package and not the kernel-debug-modules-extra package as distributed by Rocky-Linux. See How to fix? for Rocky-Linux:9 relevant fixed versions and status.

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

smb: client: validate the whole DACL before rewriting it in cifsacl

build_sec_desc() and id_mode_to_cifs_acl() derive a DACL pointer from a server-supplied dacloffset and then use the incoming ACL to rebuild the chmod/chown security descriptor.

The original fix only checked that the struct smb_acl header fits before reading dacl_ptr->size or dacl_ptr->num_aces. That avoids the immediate header-field OOB read, but the rewrite helpers still walk ACEs based on pdacl->num_aces with no structural validation of the incoming DACL body.

A malicious server can return a truncated DACL that still contains a header, claims one or more ACEs, and then drive replace_sids_and_copy_aces() or set_chmod_dacl() past the validated extent while they compare or copy attacker-controlled ACEs.

Factor the DACL structural checks into validate_dacl(), extend them to validate each ACE against the DACL bounds, and use the shared validator before the chmod/chown rebuild paths. parse_dacl() reuses the same validator so the read-side parser and write-side rewrite paths agree on what constitutes a well-formed incoming DACL.

CVSS Base Scores

version 3.1