Improper Link Resolution Before File Access ('Link Following') vulnerability in
QFileSystemEngine in the Qt corelib module on Windows potentially allows
Symlink Attacks and the use of Malicious Files. This vulnerability has been
discovered and assigned the CVE ID CVE-2025-4211. The issue originates from
CVE-2024-38081. The vulnerability arises from the use of the GetTempPath API,
which can be exploited by attackers to manipulate temporary file paths,
potentially leading to unauthorized access and privilege escalation. The
affected public API in the Qt Framework is QDir::tempPath() and anything that
uses it, such as QStandardPaths with TempLocation, QTemporaryDir, and
QtemporaryFile.
Affected versions:
All version of Qt up to and including 5.15.18, from 6.0.0 through 6.5.8, from
6.6.0 through 6.8.1. It is fixed in Qt 5.15.19, Qt 6.5.9, Qt 6.8.2, Qt 6.9.0
Impact:
The vulnerability allows attackers to influence the temporary file path
resolution, which can lead to elevation of privilege. This can be particularly
dangerous if exploited by unprivileged users to gain higher-level access or
execute arbitrary code with elevated permissions.
Attack Vectors:
An attacker with local access can exploit symbolic link attacks. The default
temporary directory for system/privileged processes allows regular unprivileged
users to create files, including following symlinks, and thus place privileged
files and directories where they shouldn't be.
Vulnerability Score:
CVSS v4.0: 7.3
Solution: Apply the following patch or update to Qt 6.9.0 or 6.8.2 or 6.5.9 or
5.15.19
Patches:
6.8: https://codereview.qt-project.org/c/qt/qtbase/+/635127 or
https://download.qt.io/official_releases/qt/6.8/CVE-2025-4211-qtbase-6.8.diff
6.5: https://codereview.qt-project.org/c/qt/tqtc-qtbase/+/635259 or
https://download.qt.io/official_releases/qt/6.5/CVE-2025-4211-qtbase-6.5.diff
5.15: https://codereview.qt-project.org/c/qt/tqtc-qtbase/+/635550 or
https://download.qt.io/official_releases/qt/5.15/CVE-2025-4211-qtbase-5.15.diff
______________________
Tuukka Kettunen
Senior Manager, Technical Support
[cid:[email protected]]<https://www.qt.io/>
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