Use after free in QHttp2ProtocolHandler

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-5991
StatePUBLISHED
AssignerTQtC
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-06-11 08:15:22 UTC
Updated2026-07-29 10:16:36 UTC
DescriptionThere 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.

Risk And Classification

Primary CVSS: v4.0 2.1 LOW from a59d8014-47c4-4630-ab43-e1b13cbe58e3

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.001190000 probability, percentile 0.020650000 (date 2026-07-30)

Problem Types: CWE-416 | CWE-416 CWE-416 Use After Free

VersionSourceTypeScoreSeverityVector
4.0a59d8014-47c4-4630-ab43-e1b13cbe58e3Secondary2.1LOWCVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/E:X/C...
4.0CNACVSS2.1LOWCVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L

CVSS v4.0 Breakdown

Attack Vector
Local
Attack Complexity
High
Attack Requirements
None
Privileges Required
None
User Interaction
None
Confidentiality
Low
Integrity
Low
Availability
Low
Sub Conf.
Low
Sub Integrity
Low
Sub Availability
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Qt Qt unaffected 6.9.0 python Not specified
CNA Qt Qt affected 6.9.0 Not specified
CNA Qt Qt unaffected 6.9.1 Not specified

References

ReferenceSourceLinkTags
codereview.qt-project.org/c/qt/qtbase/+/643777 a59d8014-47c4-4630-ab43-e1b13cbe58e3 codereview.qt-project.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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