---
id: CVE-2026-16762
title: >-
  Denial-of-service vulnerability in the Qt Core QXmlStream parser
  (QXmlStreamReader) impacts Qt
summary: >-
  An attacker able to supply a crafted XML document to an application using
  QXmlStreamReader can cause disproportionate CPU consumption during parsing,
  making the application unresponsive (denial of service). Exploitation requires
  only tha…
severity: high
cvss: 8.7
cvssVector: >-
  CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/S:P/AU:Y/R:A/RE:L
cvssSource: cna
cwe:
  - CWE-407
vendor: qt
product: qt
affected:
  - qt >= 4.3.0 < 6.8.9
  - qt >= 6.9.0 < 6.11.2
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-23T10:43:53.436456Z'
published: '2026-10-23'
updated: '2026-10-23'
sourceUpdated: '2026-10-23T10:56:05.830Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-16762'
references:
  - url: >-
      https://wiki.qt.io/List_of_known_vulnerabilities_in_Qt_products#CVE-2026-16762:
  - url: 'https://codereview.qt-project.org/c/qt/qtbase/+/738885'
  - url: 'https://codereview.qt-project.org/c/qt/qtbase/+/738901'
tags:
  - cve.org
ingestedAt: '2026-10-23T09:20:44.055Z'
---

## Overview

An attacker able to supply a crafted XML document to an application using QXmlStreamReader can cause disproportionate CPU consumption during parsing, making the application unresponsive (denial of service). Exploitation requires only that the application parse attacker-influenced XML; no authentication, privileges, or user interaction beyond ingesting the input are needed. There is no loss of confidentiality or integrity — no data disclosure, data modification, or code execution — and the impact is contained to the affected process.

## Affected

- `qt >= 4.3.0 < 6.8.9`
- `qt >= 6.9.0 < 6.11.2`

## Remediation

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