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Vulnerabilities

Vulnerability · CVE-2025-6338

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.

Published Oct 16, 2025 · catalog updated Jul 29, 2026 · Qt Qt

Last checked Oct 27, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2025-6338. EPSS is 0.43%. Act only if a listed version of Qt Qt is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Critical9.2
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.43%
Remediation
Vendor / distro source
Affected products
vendor Qt Qt 5.15.0 ≤6.8.3

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor Qt Qt 5.15.0 ≤6.8.35.15.0 ≤6.8.3

How to fix CVE-2025-6338

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2025-6338. EPSS is 0.43%. Act only if a listed version of Qt Qt is installed.

Which versions are affected?

Compare what you have installed with Qt Qt 5.15.0 ≤6.8.3 5.15.0 ≤6.8.3. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.43%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Windows security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 16, 2025 · EUVD

    Detected

    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.

  2. Jul 29, 2026 · EUVD

    Updated

    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.

Sources

  • CVE.orgVulnerability recordCVE-2025-6338

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-6338

    30-day exploitation probability 0.43%

    first.org
  • EUVDVulnerability recordEUVD-2025-34743

    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.

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Oct 27, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 27, 2026
  • CVE.orgOct 23, 2026
  • EUVDOct 23, 2026