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Echo: linux: security update to 6.1.176-1

high Tenable Cloud Security Plugin ID 460672

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

 - In the Linux kernel, the following vulnerability has been resolved: ksmbd: require minimum ACE size in
 smb_check_perm_dacl() Both ACE-walk loops in smb_check_perm_dacl() only guard against an under-sized
 remaining buffer, not against an ACE whose declared `ace->size` is smaller than the struct it claims to
 describe: if (offsetof(struct smb_ace, access_req) > aces_size) break; ace_size = le16_to_cpu(ace->size);
 if (ace_size > aces_size) break; The first check only requires the 4-byte ACE header to be in bounds; it
 does not require access_req (4 bytes at offset 4) to be readable. An attacker who has set a crafted DACL
 on a file they own can declare ace->size == 4 with aces_size == 4, pass both checks, and then granted |=
 le32_to_cpu(ace->access_req); /* upper loop */ compare_sids(&sid, &ace->sid); /* lower loop */ reads
 access_req at offset 4 (OOB by up to 4 bytes) and ace->sid at offset 8 (OOB by up to CIFS_SID_BASE_SIZE +
 SID_MAX_SUB_AUTHORITIES * 4 bytes). Tighten both loops to require ace_size >= offsetof(struct smb_ace,
 sid) + CIFS_SID_BASE_SIZE which is the smallest valid on-wire ACE layout (4-byte header + 4-byte
 access_req + 8-byte sid base with zero sub-auths). Also reject ACEs whose sid.num_subauth exceeds
 SID_MAX_SUB_AUTHORITIES before letting compare_sids() dereference sub_auth[] entries. parse_sec_desc()
 already enforces an equivalent check (lines 441-448); smb_check_perm_dacl() simply grew weaker validation
 over time. Reachability: authenticated SMB client with permission to set an ACL on a file. On a subsequent
 CREATE against that file, the kernel walks the stored DACL via smb_check_perm_dacl() and triggers the OOB
 read. Not pre-auth, and the OOB read is not reflected to the attacker, but KASAN reports and kernel state
 corruption are possible. (CVE-2026-31712)

Solution

Update the linux library and its related packages to version 6.1.176-1 or later.

See Also

https://advisory.echohq.com/cve/CVE-2026-31712

Plugin Details

Severity: High

ID: 460672

Version: Revision 1.1

Type: Local

Published: 10/2/2026

Updated: 10/2/2026

Risk Information

VPR

Risk Factor: Medium

Score: 4.5

Percentile: 57.4

CVSS v2

Risk Factor: High

Base Score: 8.7

Temporal Score: 6.4

Vector: CVSS2#AV:N/AC:L/Au:S/C:C/I:P/A:C

CVSS Score Source: CVE-2026-31712

CVSS v3

Risk Factor: High

Base Score: 8.3

Temporal Score: 7.2

Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

Exploit Ease: No known exploits are available

Patch Publication Date: 5/2/2026

Vulnerability Publication Date: 5/1/2026

Reference Information

CVE: CVE-2026-31712