Description

An issue was found in the private API function qDecodeDataUrl() in QtCore, which is used in QTextDocument and QNetworkReply, and, potentially, in user code.

If the function was called with malformed data, for example, an URL that
contained a "charset" parameter that lacked a value (such as
"data:charset,"), and Qt was built with assertions enabled, then it would hit an assertion, resulting in a denial of service
(abort).

This impacts Qt up to 5.15.18, 6.0.0->6.5.8, 6.6.0->6.8.3 and 6.9.0. This has been fixed in 5.15.19, 6.5.9, 6.8.4 and 6.9.1.

Classification

CVE ID: CVE-2025-5455

CVSS Base Severity: HIGH

CVSS Base Score: 8.4

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:H/SC:N/SI:H/SA:H/R:U/RE:M/U:Clear

Affected Products

Vendor: The Qt Company

Product: Qt

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.06% (probability of being exploited)

EPSS Percentile: 20.1% (scored less or equal to compared to others)

EPSS Date: 2025-06-07 (when was this score calculated)

References

https://nvd.nist.gov/vuln/detail/CVE-2025-5455
https://codereview.qt-project.org/c/qt/qtbase/+/642006

Timeline