---
id: CVE-2026-64046
title: 'net: tls: prevent chain-after-chain in plain text SG'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: tls: prevent chain-after-chain in plain text SG

  Sashiko points out that if end = 0 (start != 0) the current
  code will create a chain link to content type right af…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec <
    49a5faaa471ddcd37b6893970c9916eb836e7c31
  - >-
    Linux >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec <
    91359966e247c0244c66d50bbb8e74aefa4321c3
  - >-
    Linux >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec <
    410351158dfef2d67fea6603680b3a6013c6ed9d
  - >-
    Linux >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec <
    acdc12b71c9aa4be5dcd2c8062753c6d2033e235
  - >-
    Linux >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec <
    929b1548e63ac72e104c07d8ee8cbbeeba2fa89a
  - >-
    Linux >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec <
    af855f4c966afafef74faf8390c7b86568c0d46d
  - >-
    Linux >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec <
    b9c015ef1a7bf1e8dc67f21c6381f36deb2c3a36
  - >-
    Linux >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec <
    ff26a0e8377dec07e4a7230db7675bed1b9a6d03
  - Linux d529d6c9f7e3aaeac13c4948f79799ccb825f29d
  - Linux >= 5.4.14 < 5.5
  - Linux 5.5
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-16T15:35:52.163580Z'
published: '2026-07-19'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:42:20.684Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-64046'
references:
  - url: 'https://git.kernel.org/stable/c/49a5faaa471ddcd37b6893970c9916eb836e7c31'
  - url: 'https://git.kernel.org/stable/c/91359966e247c0244c66d50bbb8e74aefa4321c3'
  - url: 'https://git.kernel.org/stable/c/410351158dfef2d67fea6603680b3a6013c6ed9d'
  - url: 'https://git.kernel.org/stable/c/acdc12b71c9aa4be5dcd2c8062753c6d2033e235'
  - url: 'https://git.kernel.org/stable/c/929b1548e63ac72e104c07d8ee8cbbeeba2fa89a'
  - url: 'https://git.kernel.org/stable/c/af855f4c966afafef74faf8390c7b86568c0d46d'
  - url: 'https://git.kernel.org/stable/c/b9c015ef1a7bf1e8dc67f21c6381f36deb2c3a36'
  - url: 'https://git.kernel.org/stable/c/ff26a0e8377dec07e4a7230db7675bed1b9a6d03'
tags:
  - cve.org
epss: 0.00514
epssPercentile: 0.4249
ingestedAt: '2026-10-16T17:24:46.792Z'
---

## Overview

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

net: tls: prevent chain-after-chain in plain text SG

Sashiko points out that if end = 0 (start != 0) the current
code will create a chain link to content type right after
the wrap link:

  This would create a chain where the wrap link points directly
  to another chain link. The scatterlist API sg_next iterator
  does not recursively resolve consecutive chain links.

meaning this is illegal input to crypto.

The wrapping link is unnecessary if end = 0. end is the entry after
the last one used so end = 0 means there's nothing pushed after
the wrap:

   end         start            i
    v            v              v
  [   ]...[   ][ d ][ d ][ d ][ d ][rsv for wrap]

Skip the wrapping in this case.

TLS 1.3 can use the "wrapping slot" for it's chaining if end = 0.
This avoids the chain-after-chain.

Move the wrap chaining before marking END and chaining off content
type, that feels like more logical ordering to me, but should not
matter from functional perspective.

## Affected

- `Linux >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec < 49a5faaa471ddcd37b6893970c9916eb836e7c31`
- `Linux >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec < 91359966e247c0244c66d50bbb8e74aefa4321c3`
- `Linux >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec < 410351158dfef2d67fea6603680b3a6013c6ed9d`
- `Linux >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec < acdc12b71c9aa4be5dcd2c8062753c6d2033e235`
- `Linux >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec < 929b1548e63ac72e104c07d8ee8cbbeeba2fa89a`
- `Linux >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec < af855f4c966afafef74faf8390c7b86568c0d46d`
- `Linux >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec < b9c015ef1a7bf1e8dc67f21c6381f36deb2c3a36`
- `Linux >= 9aaaa56845a06aeabdd597cbe19492dc01f281ec < ff26a0e8377dec07e4a7230db7675bed1b9a6d03`
- `Linux d529d6c9f7e3aaeac13c4948f79799ccb825f29d`
- `Linux >= 5.4.14 < 5.5`
- `Linux 5.5`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.