---
id: CVE-2026-95509
title: >-
  Strings optimized for Latin-1 displaying Latin-1 characters cause incorrect
  String.arg() formatting by an incorrect buffer size calculation, causing
  out-of-bounds reading.
summary: >-
  Strings optimized for Latin-1 displaying Latin-1 characters cause incorrect
  String.arg() formatting by an incorrect buffer size calculation, causing
  out-of-bounds reading.
severity: high
cvss: 8.8
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N'
cwe:
  - CWE-125
  - CWE-131
vendor: qt
product: Qt for MCUs
affected:
  - for_mcus >= 2.6.0 < 2.11.3
  - for_mcus >= 2.12.0 < 2.12.3
published: '2026-09-29'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T16:30:42.327'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-95509'
references:
  - url: >-
      https://wiki.qt.io/List_of_known_vulnerabilities_in_Qt_products#CVE-2026-95509:
    label: a59d8014-47c4-4630-ab43-e1b13cbe58e3
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-95509.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-95509'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2543059'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-95509'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-95509'
  - url: 'https://access.redhat.com/errata/RHSA-2026:80566'
  - url: 'https://access.redhat.com/errata/RHSA-2026:80569'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00312
epssPercentile: 0.23881
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-29T15:02:05.437104Z'
cvssSource: cna
ingestedAt: '2026-09-29T11:32:41.244Z'
patched:
  - hardened_images
scores:
  cna: 8.8
  vendor: 8.2
---

## Overview

Strings optimized for Latin-1 displaying Latin-1 characters cause incorrect String.arg() formatting by an incorrect buffer size calculation, causing out-of-bounds reading.

## Remediation

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

## Vendor advisories

- **RHSA-2026:80566** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-10-12 · [advisory](https://access.redhat.com/errata/RHSA-2026:80566)
- **RHSA-2026:80569** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-10-12 · [advisory](https://access.redhat.com/errata/RHSA-2026:80569)