Security Bulletin
This security bulletin contains one medium risk vulnerability.
EUVDB-ID: #VU112058
Risk: Medium
CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green]
CVE-ID: CVE-2025-5991
CWE-ID:
CWE-416 - Use After Free
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a use-after-free error within the QHttp2ProtocolHandler in the QtNetwork module. A remote attacker can trigger a race condition between QHttp2Stream HTTP POST uploads and simultaneous handling of HTTP error responses and perform a denial of service (DoS) attack.
MitigationInstall updates from vendor's website.
Vulnerable software versionsQt: 6.9.0
CPE2.3 External linkshttps://codereview.qt-project.org/c/qt/qtbase/+/643777
https://www.qt.io/blog/security-advisory-recently-discovered-use-after-free-issue-in-qhttp2protocolhandler-impacts-qt
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.