---
id: CVE-2026-43341
title: 'net/ipv6: ioam6: prevent schema length wraparound in trace fill'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net/ipv6: ioam6: prevent schema length wraparound in trace fill

  ioam6_fill_trace_data() stores the schema contribution to the trace
  length in a u8. With bit 22 enabled…
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 >= 8c6f6fa6772696be0c047a711858084b38763728 <
    d3a1fb2ca323d7a4e10ab3afbfa25e6d8921e4f2
  - >-
    Linux >= 8c6f6fa6772696be0c047a711858084b38763728 <
    e96d48b37708d53cbdc47f6f60b0714fc4a5f596
  - >-
    Linux >= 8c6f6fa6772696be0c047a711858084b38763728 <
    d1b041080086e91d3733a5438a8c51ad5d3d8e09
  - >-
    Linux >= 8c6f6fa6772696be0c047a711858084b38763728 <
    77695a69baca9b99d95fad09fc78c2318736604f
  - >-
    Linux >= 8c6f6fa6772696be0c047a711858084b38763728 <
    184d2e9db27c0f76226b5cad16fe29510a5d2280
  - >-
    Linux >= 8c6f6fa6772696be0c047a711858084b38763728 <
    d6e1c9b02d85a4f1f4ba6d68e916d9b610a3ed7d
  - >-
    Linux >= 8c6f6fa6772696be0c047a711858084b38763728 <
    5e67ba9bb531e1ec6599a82a065dea9040b9ce50
  - Linux 5.15
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-16T15:16:35.670723Z'
published: '2026-05-08'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:20:39.491Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-43341'
references:
  - url: 'https://git.kernel.org/stable/c/d3a1fb2ca323d7a4e10ab3afbfa25e6d8921e4f2'
  - url: 'https://git.kernel.org/stable/c/e96d48b37708d53cbdc47f6f60b0714fc4a5f596'
  - url: 'https://git.kernel.org/stable/c/d1b041080086e91d3733a5438a8c51ad5d3d8e09'
  - url: 'https://git.kernel.org/stable/c/77695a69baca9b99d95fad09fc78c2318736604f'
  - url: 'https://git.kernel.org/stable/c/184d2e9db27c0f76226b5cad16fe29510a5d2280'
  - url: 'https://git.kernel.org/stable/c/d6e1c9b02d85a4f1f4ba6d68e916d9b610a3ed7d'
  - url: 'https://git.kernel.org/stable/c/5e67ba9bb531e1ec6599a82a065dea9040b9ce50'
tags:
  - cve.org
epss: 0.00774
epssPercentile: 0.54881
ingestedAt: '2026-10-16T17:24:46.692Z'
---

## Overview

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

net/ipv6: ioam6: prevent schema length wraparound in trace fill

ioam6_fill_trace_data() stores the schema contribution to the trace
length in a u8. With bit 22 enabled and the largest schema payload,
sclen becomes 1 + 1020 / 4, wraps from 256 to 0, and bypasses the
remaining-space check. __ioam6_fill_trace_data() then positions the
write cursor without reserving the schema area but still copies the
4-byte schema header and the full schema payload, overrunning the trace
buffer.

Keep sclen in an unsigned int so the remaining-space check and the write
cursor calculation both see the full schema length.

## Affected

- `Linux >= 8c6f6fa6772696be0c047a711858084b38763728 < d3a1fb2ca323d7a4e10ab3afbfa25e6d8921e4f2`
- `Linux >= 8c6f6fa6772696be0c047a711858084b38763728 < e96d48b37708d53cbdc47f6f60b0714fc4a5f596`
- `Linux >= 8c6f6fa6772696be0c047a711858084b38763728 < d1b041080086e91d3733a5438a8c51ad5d3d8e09`
- `Linux >= 8c6f6fa6772696be0c047a711858084b38763728 < 77695a69baca9b99d95fad09fc78c2318736604f`
- `Linux >= 8c6f6fa6772696be0c047a711858084b38763728 < 184d2e9db27c0f76226b5cad16fe29510a5d2280`
- `Linux >= 8c6f6fa6772696be0c047a711858084b38763728 < d6e1c9b02d85a4f1f4ba6d68e916d9b610a3ed7d`
- `Linux >= 8c6f6fa6772696be0c047a711858084b38763728 < 5e67ba9bb531e1ec6599a82a065dea9040b9ce50`
- `Linux 5.15`

## Remediation

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