Critical severity · published Oct 16, 2025
CVE-2025-6338
Possible denial of service with multiple incoming connections to a Schannel based server with a TLS backend
9.2
CVSS
0.4%
EPSS
No
On KEV
Description
There is an incomplete cleanup vulnerability in Qt Network's Schannel support on Windows which can lead to a Denial of Service over a long period.
This issue affects Qt from 5.15.0 through 6.8.3, from 6.9.0 before 6.9.2.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 37% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
QT
Qt · Qt
5.15.0 through 6.8.3; 6.9.0 before 6.9.2 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-6338
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-6338
codereview.qt-project.org
https://codereview.qt-project.org/c/qt/qtbase/+/651495
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