# CVE-2026-78253: Qt stack exhaustion in QXmlStreamReader::readElementText

Source: https://junglewise.ai/threats/cve-2026-78253-uncontrolled-recursion-in-qxmlstreamreader-readelementtext-in-qt  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-23. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-78253 · Severity: info · Published 2026-09-23

Qt is a cross-platform development framework used in many desktop and embedded applications. A vulnerability in Qt's XML parsing allows an attacker to crash applications by providing a specially crafted XML document that causes uncontrolled recursion. An application that processes untrusted XML files could be rendered unavailable through this denial of service attack.

Technologies: [Qt Group Qt](https://junglewise.ai/threats/technologies/qt-group-qt). Vendors: [Qt Group](https://junglewise.ai/threats/vendors/qt-group).

## Quick answers

**Is CVE-2026-78253 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-78253 being exploited in the wild.

**How severe is CVE-2026-78253?** Informational severity, published 23 September 2026.

**Which products and versions are affected?** Qt Group Qt <UNKNOWN>.

**Is there a fix for CVE-2026-78253?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-78253 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-78253?** Check whether you run Qt Group Qt at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

Uncontrolled recursion in QXmlStreamReader::readElementText() allows stack exhaustion when processing deeply nested XML structures. An attacker can exploit this by sending a crafted XML document to any application using the vulnerable Qt XML parsing API. The attack requires no authentication or user interaction beyond the application processing the malicious XML input; successful exploitation crashes the affected application.

## Affected products

- Qt Group Qt <UNKNOWN>

## Timeline

- 2026-09-23: disclosed

## References

- [https://codereview.qt-project.org/c/qt/qtbase/+/754345](https://codereview.qt-project.org/c/qt/qtbase/+/754345)

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- [Qt Network QAuthenticator NTLM out-of-bounds read](https://junglewise.ai/threats/cve-2026-105946-out-of-bounds-read-in-the-qauthenticator-ntlm-authentication)
- [Qt null pointer dereference in QNetworkAccessManager HTTP/2](https://junglewise.ai/threats/cve-2026-96432-a-malicious-or-compromised-http-2-server-withholding-settings-ack)