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Echo: linux: security update to 6.1.170-1

critical Tenable Cloud Security Plugin ID 461969

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: mptcp: fix slab-use-after-free in
 __inet_lookup_established The ehash table lookups are lockless and rely on SLAB_TYPESAFE_BY_RCU to
 guarantee socket memory stability during RCU read-side critical sections. Both tcp_prot and tcpv6_prot
 have their slab caches created with this flag via proto_register(). However, MPTCP's mptcp_subflow_init()
 copies tcpv6_prot into tcpv6_prot_override during inet_init() (fs_initcall, level 5), before inet6_init()
 (module_init/device_initcall, level 6) has called proto_register(&tcpv6_prot). At that point,
 tcpv6_prot.slab is still NULL, so tcpv6_prot_override.slab remains NULL permanently. This causes MPTCP v6
 subflow child sockets to be allocated via kmalloc (falling into kmalloc-4k) instead of the TCPv6 slab
 cache. The kmalloc-4k cache lacks SLAB_TYPESAFE_BY_RCU, so when these sockets are freed without
 SOCK_RCU_FREE (which is cleared for child sockets by design), the memory can be immediately reused.
 Concurrent ehash lookups under rcu_read_lock can then access freed memory, triggering a slab-use-after-
 free in __inet_lookup_established. Fix this by splitting the IPv6-specific initialization out of
 mptcp_subflow_init() into a new mptcp_subflow_v6_init(), called from mptcp_proto_v6_init() before protocol
 registration. This ensures tcpv6_prot_override.slab correctly inherits the SLAB_TYPESAFE_BY_RCU slab
 cache. (CVE-2026-31669)

Solution

Update the linux library and its related packages to version 6.1.170-1 or later.

See Also

https://advisory.echohq.com/cve/CVE-2026-31669

Plugin Details

Severity: Critical

ID: 461969

Version: Revision 1.1

Type: Local

Published: 10/2/2026

Updated: 10/2/2026

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 57.94

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.4

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

CVSS Score Source: CVE-2026-31669

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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: 5/1/2026

Vulnerability Publication Date: 4/23/2026

Reference Information

CVE: CVE-2026-31669