CVE-2025-5991: CWE-416 Use After Free in Qt
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.
AI Analysis
Technical Summary
This vulnerability is a Use After Free (CWE-416) in Qt's QHttp2ProtocolHandler within the QtNetwork module, specifically impacting HTTP/2 functionality. It occurs due to a race condition between QHttp2Stream uploading the body of a POST request and concurrent processing of HTTP error responses. Only Qt 6.9.0 is affected, and the flaw was resolved in Qt 6.9.1.
Potential Impact
The vulnerability could potentially lead to memory corruption due to use-after-free conditions during HTTP/2 POST request processing. However, the low CVSS score (2.1) and lack of known exploits in the wild indicate limited impact and exploitability. HTTP/1.x handling is not affected.
Mitigation Recommendations
Upgrade affected Qt installations from version 6.9.0 to 6.9.1 or later, where this vulnerability has been fixed. No other mitigation is required as the issue is resolved in the official patch.
CVE-2025-5991: CWE-416 Use After Free in Qt
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.
CVSS v4.0
Score 2.1low
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability is a Use After Free (CWE-416) in Qt's QHttp2ProtocolHandler within the QtNetwork module, specifically impacting HTTP/2 functionality. It occurs due to a race condition between QHttp2Stream uploading the body of a POST request and concurrent processing of HTTP error responses. Only Qt 6.9.0 is affected, and the flaw was resolved in Qt 6.9.1.
Potential Impact
The vulnerability could potentially lead to memory corruption due to use-after-free conditions during HTTP/2 POST request processing. However, the low CVSS score (2.1) and lack of known exploits in the wild indicate limited impact and exploitability. HTTP/1.x handling is not affected.
Mitigation Recommendations
Upgrade affected Qt installations from version 6.9.0 to 6.9.1 or later, where this vulnerability has been fixed. No other mitigation is required as the issue is resolved in the official patch.
Technical Details
- Data Version
- 5.1
- Assigner Short Name
- TQtC
- Date Reserved
- 2025-06-11T06:08:23.434Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6849339d72c9cfbdf1192f41
Added to database: 06/11/2025, 07:43:25 UTC
Last enriched: 07/29/2026, 21:36:18 UTC
Last updated: 09/10/2026, 19:36:51 UTC
Views: 113
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