Memory leak in Qt - CVE-2020-13962
Published: March 6, 2026
Vulnerability identifier: #VU123611
CSH Severity: Medium
CVSS v4: 6.9 [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]
CVE-ID: CVE-2020-13962
CWE-ID: CWE-401
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to perform DoS attack on the target system.
The vulnerability exists due memory leak when handling TLS connections. A remote attacker can force the application to leak random memory parts to unrelated TLS sessions and cause a denial of service to QSslSocket users.
Affected software
Qt
Ubuntu
qtbase-opensource-src (Ubuntu package)
Ubuntu
qtbase-opensource-src (Ubuntu package)
How to mitigate CVE-2020-13962
Install updates from vendor's website.
Qt - addressed in versions 5.12.9, 5.15.0
qtbase-opensource-src (Ubuntu package) - addressed in versions 5.5.1+dfsg-16ubuntu7.7+esm2, 5.9.5+dfsg-0ubuntu2.6+esm2, 5.12.8+dfsg-0ubuntu2.1+esm3, 5.15.3+dfsg-2ubuntu0.2+esm3, 5.15.13+dfsg-1ubuntu1+esm1
qtbase-opensource-src (Ubuntu package) - addressed in versions 5.5.1+dfsg-16ubuntu7.7+esm2, 5.9.5+dfsg-0ubuntu2.6+esm2, 5.12.8+dfsg-0ubuntu2.1+esm3, 5.15.3+dfsg-2ubuntu0.2+esm3, 5.15.13+dfsg-1ubuntu1+esm1