CVE-2025-5991 | BDVDB-2026-282256 Detail

QtQt

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.

Impact#

Per CVSS v4.0: confidentiality impact low, integrity impact low, availability impact low. Attack vector: local.

Weaknesses#

CWE-416 Use After Free

References#

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

Exploit#

No public exploit known

History#

Version 12025-06-11Record published in the CVE List.
Version 22026-07-29Most recent update recorded in the CVE List.

Published

Published: 2025-06-11
Last modified: 2026-07-29

Vendor information

Vendor: Qt
Product: Qt

All Qt vulnerabilities

Score

2.1 Low

EPSS

less than 1%, Very Low

Estimated chance of exploitation in the next 30 days. EPSS percentile: 3.5.

KEV

Not listed in the CISA Known Exploited Vulnerabilities catalog.

Impact

Memory Corruption

Action

No specific action is recorded in the source data. Check the references for vendor guidance.

Affected Systems

Vulnerable
Not stated
Fixed
0
Vulnerable
6.9.0
Fixed
Not stated
Vulnerable
Not stated
Fixed
6.9.1

Scoring System

CVSS v4.0

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

Metric breakdown
Attack Vector	Local
Attack Complexity	High
Attack Requirements	None
Privileges Required	None
User Interaction	None
Vulnerable System Confidentiality	Low
Vulnerable System Integrity	Low
Vulnerable System Availability	Low
Subsequent System Confidentiality	Low
Subsequent System Integrity	Low
Subsequent System Availability	Low

CVSS v3.1

Not available

CVSS v3.0

Not available

CVSS v2

Not available

Source: CVE List v5 (record); CISA KEV (kev, action); FIRST EPSS (epss).