CVE-2025-5991
There is a "Use After Free" vulnerability in Qt's QHttp2ProtocolHandler in the QtNetwork module.
Overview
CVE-2025-5991 is a known-severity vulnerability. It was published on June 11, 2025.
Technical 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.
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
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Frequently asked questions
What is CVE-2025-5991?
CVE-2025-5991 is a known-severity vulnerability. It was published on June 11, 2025.
How severe is CVE-2025-5991?
CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.
How do I fix or remediate CVE-2025-5991?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2025-5991?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2025-5991 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.