CVE-2025-5991

2.1 lowEPSS 0.1%

Low (2.1). EPSS 0.1% chance of exploitation in the next 30 days.

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.

Severity

CVSS 4.0

2.1 low

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

EPSS: 0.1% chance of exploitation in the next 30 days; higher than 3% of CVEs (scores of 2026-10-31)
CWE: CWE-416
Published: 2025-06-11
Modified: 2026-07-29
Record from: the NVD, synced 2026-10-19

References

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

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