CVE-2026-78253 Denial-of-service (stack-exhaustion) vulnerability in QXmlStreamReader::readElementText() impacts Qt
Attackers can crash applications using Qt's XML reader by sending crafted XML documents that cause stack exhaustion.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-78253?
CVE-2026-78253 is a low-severity denial of service vulnerability in qt, published on 23 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Uncontrolled recursion in QXmlStreamReader::readElementText() in Qt Group Qt allows attackers to cause a denial of service (application crash via stack exhaustion) via a crafted XML document.
Weakness: CWE-674
Which versions are affected by CVE-2026-78253?
How do I fix CVE-2026-78253?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-78253 being exploited?
There is no known exploitation of CVE-2026-78253 in the wild and no public exploit code.
Sources
Also known as AZL-106827, DEBIAN-CVE-2026-78253, ECHO-abe8-219d-6f61, GHSA-cpqc-q57w-7c2q, UBUNTU-CVE-2026-78253.