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Critical 9.2Published Oct 16, 2025

CVE-2025-6338Possible denial of service with multiple incoming connections to a Schannel based server with a TLS backend

Updated under an hour ago ()

Does this affect you?

It affects Qt. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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.

CVSS
9.2 CRITICAL (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H
Weakness (CWE)
CWE-459
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
TQtC
NVD analysis
Deferred
Record last updated
Jul 29, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
Qt Qt
qt:qt (from the name)
before 5.15.0 not affected; from 5.15.0 through 6.8.3; from 6.8.4 before 6.9.0 not affected; from 6.9.0 before 6.9.2
CNA record

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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