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.
References (1)
Core 1
Core References
Various Sources
https://codereview.qt-project.org/c/qt/qtbase/+/643777
Scores
CVSS v4
2.1
EPSS
0.0012
EPSS Percentile
2.1%
CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
partial
Details
CWE
CWE-416
Status
published
Products (3)
The Qt Company/Qt
< 6.9.0
The Qt Company/Qt
6.9.0
The Qt Company/Qt
6.9.1
Published
Jun 11, 2025
Tracked Since
Feb 18, 2026