Echo: linux: security update to 6.1.176-1

high Tenable Self-Hosted Container Security Plugin ID 463486

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: smb: server: fix active_num_conn leak
on transport allocation failure Commit 77ffbcac4e56 ("smb: server: fix leak of active_num_conn in
ksmbd_tcp_new_connection()") addressed the kthread_run() failure path. The earlier alloc_transport() ==
NULL path in the same function has the same leak, is reachable pre-authentication via any TCP connect to
port 445, and was empirically reproduced on UML (ARCH=um, v7.0-rc7): a small number of forced allocation
failures were sufficient to put ksmbd into a state where every subsequent connection attempt was rejected
for the remainder of the boot. ksmbd_kthread_fn() increments active_num_conn before calling
ksmbd_tcp_new_connection() and discards the return value, so when alloc_transport() returns NULL the
socket is released and -ENOMEM returned without decrementing the counter. Each such failure permanently
consumes one slot from the max_connections pool; once cumulative failures reach the cap,
atomic_inc_return() hits the threshold on every subsequent accept and every new connection is rejected.
The counter is only reset by module reload. An unauthenticated remote attacker can drive the server toward
the memory pressure that makes alloc_transport() fail by holding open connections with large RFC1002
lengths up to MAX_STREAM_PROT_LEN (0x00FFFFFF); natural transient allocation failures on a loaded host
produce the same drift more slowly. Mirror the existing rollback pattern in ksmbd_kthread_fn(): on the
alloc_transport() failure path, decrement active_num_conn gated on server_conf.max_connections. Repro
details: with the patch reverted, forced alloc_transport() NULL returns leaked counter slots and
subsequent connection attempts -- including legitimate connects issued after the forced-fail window had
closed -- were all rejected with "Limit the maximum number of connections". With this patch applied, the
same connect sequence produces no rejections and the counter cycles cleanly between zero and one on every
accept. (CVE-2026-31711)

Solution

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

Plugin Details

Severity: High

ID: 463486

Version: Revision 1.1

Type: Local

Family: Echo Local Security Checks

Published: 10/2/2026

Updated: 10/2/2026

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.66

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

CVSS Score Source: CVE-2026-31711

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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-2026-31711

Detections

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