Log in Start free

Vulnerability · Published Jun 11, 2025 · Assigned by TQtC

CVE-2025-5991Use after free in QHttp2ProtocolHandler

Low 2.1

In plain English

A low-severity use-after-free in Qt from Qt. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 3% of all known vulnerabilities).

Severity (CVSS 4.0)2.1Low
Exploit odds (30 days)0.1%top 96.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12qt6-baseno fix listedCVE-2025-5991
Debian:13qt6-baseno fix listedCVE-2025-5991
Debian:12qtbase-opensource-srcno fix listedCVE-2025-5991
Debian:13qtbase-opensource-srcno fix listedCVE-2025-5991
Debian:12qtbase-opensource-src-glesno fix listedCVE-2025-5991
Debian:13qtbase-opensource-src-glesno fix listedCVE-2025-5991
Ubuntu:22.04:LTSqt6-baseno fix listedUBUNTU-CVE-2025-5991
Ubuntu:24.04:LTSqt6-baseno fix listedUBUNTU-CVE-2025-5991
Ubuntu:25.10qt6-baseno fix listedUBUNTU-CVE-2025-5991
Ubuntu:26.04:LTSqt6-baseno fix listedUBUNTU-CVE-2025-5991
Ubuntu:26.10qt6-baseno fix listedUBUNTU-CVE-2025-5991
Ubuntu:22.04:LTSqtbase-opensource-src-glesno fix listedUBUNTU-CVE-2025-5991
Ubuntu:24.04:LTSqtbase-opensource-src-glesno fix listedUBUNTU-CVE-2025-5991
Ubuntu:25.10qtbase-opensource-src-glesno fix listedUBUNTU-CVE-2025-5991
Ubuntu:26.04:LTSqtbase-opensource-src-glesno fix listedUBUNTU-CVE-2025-5991
Ubuntu:26.10qtbase-opensource-src-glesno fix listedUBUNTU-CVE-2025-5991

Affected products (as reported)

VendorProductVersions
Qt Qt 6.9.0

Weakness: CWE-416 · Vector: 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

References