---
id: CVE-2026-90274
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  coresight: etm4x: fix underflow for usage of (nrseqstate - 1)

  According to IHI006H Embedded Trace Macrocell Architecture
  Specification[0], TRCSEQEVR<n> is implemented …
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  coresight: etm4x: fix underflow for usage of (nrseqstate - 1)

  According to IHI006H Embedded Trace Macrocell Architecture
  Specification[0], TRCSEQEVR<n> is implemented …
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 2e1cdfe184b5202d51e0611d7a051e2bea303946 <
    8d669db59f7283b838e029af29da12e505265fae
  - >-
    Linux >= 2e1cdfe184b5202d51e0611d7a051e2bea303946 <
    4091f2d5b26d117c992ffcce1a5df425a0daedcd
  - >-
    Linux >= 2e1cdfe184b5202d51e0611d7a051e2bea303946 <
    be7b2de5b9a96ae68ffa3528e0a40d63e0fd8148
  - >-
    Linux >= 2e1cdfe184b5202d51e0611d7a051e2bea303946 <
    4f9a0f548413bf864f609c9f4bc56e3f1b3577d4
  - >-
    Linux >= 2e1cdfe184b5202d51e0611d7a051e2bea303946 <
    1ade9a335c69fc735cb7b3f222ed35ab135540fb
  - >-
    Linux >= 2e1cdfe184b5202d51e0611d7a051e2bea303946 <
    5ac900f73ce1d4d8308f40752b51bc8a02b244d2
  - >-
    Linux >= 2e1cdfe184b5202d51e0611d7a051e2bea303946 <
    1674d9bff8073bdee5dbc200f56fc3caa28d0566
  - Linux 4.2
published: '2026-09-17'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T17:17:23.997'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90274'
references:
  - url: 'https://git.kernel.org/stable/c/1674d9bff8073bdee5dbc200f56fc3caa28d0566'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/1ade9a335c69fc735cb7b3f222ed35ab135540fb'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4091f2d5b26d117c992ffcce1a5df425a0daedcd'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4f9a0f548413bf864f609c9f4bc56e3f1b3577d4'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/5ac900f73ce1d4d8308f40752b51bc8a02b244d2'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8d669db59f7283b838e029af29da12e505265fae'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/be7b2de5b9a96ae68ffa3528e0a40d63e0fd8148'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-17T16:21:47.837Z'
epss: 0.00173
epssPercentile: 0.05845
---

## Overview

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

coresight: etm4x: fix underflow for usage of (nrseqstate - 1)

According to IHI006H Embedded Trace Macrocell Architecture
Specification[0], TRCSEQEVR<n> is implemented only when
TRCIDR5.NUMSEQSTATE is 0b100, in which case n ranges from 0 to 2;
otherwise, TRCIDR5.NUMSEQSTATE is 0b000.

IOW, the number of usage in the initialisation or setting
TRCSEQEVR<n> with drvdata->nrseqstate - 1 in the loop could make
underflow issue when TRCIDR5.NUMSEQSTATE is 0b000.

Therefore, introduce nr_seq_ctrls field and untie it from nrseqstate.
As part of this introduce ETM_MAX_SEQ_TRANSITIONS macro and
apply nr_seq_ctrls and above macro to TRCSEQEVR<n> relevant fields setup.

## Remediation

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