Possible denial of service when passing malformed data in a URL to qDecodeDataUrl

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-5455
StatePUBLISHED
AssignerTQtC
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-06-02 09:15:21 UTC
Updated2026-07-29 09:16:28 UTC
DescriptionAn 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.

Risk And Classification

Primary CVSS: v4.0 8.4 HIGH from a59d8014-47c4-4630-ab43-e1b13cbe58e3

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:U/V:X/RE:M/U:Clear

EPSS: 0.003240000 probability, percentile 0.249010000 (date 2026-07-30)

Problem Types: CWE-20 | CWE-20 CWE-20 Improper Input Validation

VersionSourceTypeScoreSeverityVector
4.0a59d8014-47c4-4630-ab43-e1b13cbe58e3Secondary8.4HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:H/SC:N/SI:H/SA:H/E:X/C...
4.0CNACVSS8.4HIGHCVSS: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/R...

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
Active
Confidentiality
None
Integrity
High
Availability
High
Sub Conf.
None
Sub Integrity
High
Sub Availability
High

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:U/V:X/RE:M/U:Clear

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Qt Qt affected 5.15.18 python Not specified
CNA Qt Qt affected 6.0.0 6.5.8 python Not specified
CNA Qt Qt unaffected 6.5.9 python Not specified
CNA Qt Qt affected 6.6.0 6.8.3 python Not specified
CNA Qt Qt unaffected 6.8.4 python Not specified
CNA Qt Qt affected 6.9.0 python Not specified
CNA Qt Qt unaffected 6.9.1 python Not specified

References

ReferenceSourceLinkTags
codereview.qt-project.org/c/qt/qtbase/+/642006 a59d8014-47c4-4630-ab43-e1b13cbe58e3 codereview.qt-project.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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