Bottlerocket: bottlerocket-kernel-6.1, kernel-6.1: security update to 6.1.186bottlerocket-kernel-6.12, kernel-6.12: security update to 6.12.103bottlerocket-kernel-6.18, kernel-6.18: security update to 6.18.48

high Tenable Cloud Security Plugin ID 476073

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: net: tun: bound receive headroom
tun_get_user() uses tun->align both as skb headroom and when choosing how much packet data to keep linear.
OVS can propagate an oversized headroom request from another port to TUN or TAP. When align is larger than
the usable space in a one-page skb head, SKB_MAX_HEAD(align) underflows and the result becomes negative
when stored in good_linear. That value later wraps when assigned to the size_t linear variable, and
tun_alloc_skb() can place skb->data outside the allocated head. Bound the headroom stored by TUN to the
one-page skb-head budget and the largest non-sentinel 16-bit skb header offset. Leave one linear byte for
raw TUN and a complete Ethernet header for TAP, including NET_IP_ALIGN. Also pull the raw-TUN protocol
byte and the TAP Ethernet header before accessing them, so these checks remain safe for nonlinear skbs
supplied by other allocation paths. (CVE-2026-81000)

Solution

Update the bottlerocket-kernel-6.1 library and its related packages to version 6.1.186 or later.

Plugin Details

Severity: High

ID: 476073

Version: Revision 1.1

Type: Local

Family: Bottlerocket Local Security Checks

Published: 10/16/2026

Updated: 10/16/2026

Risk Information

VPR

Risk Factor: High

Score: 7.9

Percentile: 99.35

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5.3

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

CVSS Score Source: CVE-2026-81000

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 7

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

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

Vulnerability Information

Exploit Available: true

Exploit Ease: Exploits are available

Vulnerability Publication Date: 9/11/2026

Reference Information

CVE: CVE-2026-81000

Detections

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