CVE-2025-5991

Use after free in QHttp2ProtocolHandler

Description

There is a "Use After Free" vulnerability in Qt's QHttp2ProtocolHandler in the QtNetwork module. This only affects HTTP/2 handling, HTTP handling is not affected by this at all. This happens due to a race condition between how QHttp2Stream uploads the body of a POST request and the simultaneous handling of HTTP error responses. This issue only affects Qt 6.9.0 and has been fixed for Qt 6.9.1.

Category

2.1
CVSS
Severity: Low
CVSS 4.0 •
EPSS 0.01%
Affected: The Qt Company Qt
Published at:
Updated at:

References

Link Tags
https://codereview.qt-project.org/c/qt/qtbase/+/643777

Frequently Asked Questions

What is the severity of CVE-2025-5991?
CVE-2025-5991 has been scored as a low severity vulnerability.
How to fix CVE-2025-5991?
To fix CVE-2025-5991, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2025-5991 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2025-5991 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2025-5991?
CVE-2025-5991 affects The Qt Company Qt.
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