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Fencer Vulns
high 8.4

CVE-2025-5455 json

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

published 2025-06-02 17 mo ago modified 2026-07-29 3 mo ago also EUVD-2025-16625

cvss
8.4
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 34%
public exploits
0
none known

Summary

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.

Patch / fix

  • Qt Qt 6.5.9, 6.8.4, 6.9.1
  • qt6-base Debian 14, Debian 13 6.8.2+dfsg-8
  • qtbase-opensource-src Debian 14, Debian 13 5.15.15+dfsg-6

debian advisories DEBIAN-CVE-2025-5455

  • qt6-qtbase RHEL 10.0 6.8.1-9.el10_0
  • qt6-qtbase-gui RHEL 10.0 6.8.1-9.el10_0
  • qt6-qtbase-odbc RHEL 10.0 6.8.1-9.el10_0
  • qt6-qtbase-mysql RHEL 10.0 6.8.1-9.el10_0
  • qt6-qtbase-common RHEL 10.0 6.8.1-9.el10_0
  • qt6-qtbase-examples RHEL 10.0 6.8.1-9.el10_0
  • qt6-qtbase-postgresql RHEL 10.0 6.8.1-9.el10_0
  • qt5-qtbase RHEL 9 5.15.9-11.el9_6

red hat advisories RHSA-2025:11841RHSA-2025:9486RHSA-2025:9462

  • libqt5-qtbase SLE Module for Desktop Applications 15 SP7, SLE Module for Desktop Applications 15 SP6, SLE Module for Basesystem 15 SP7 +2 more 5.15.12+kde151-150600.3.9.1
  • qt6-base SLE Module for Package Hub 15 SP7, SLE Module for Package Hub 15 SP6, SLE Module for Desktop Applications 15 SP7 +2 more 6.6.3-150600.3.6.1
  • libqt4 SLES LTSS Extended Security 12 SP5 4.8.7-8.22.1
  • libqt4-sql-plugins SLES LTSS Extended Security 12 SP5 4.8.7-8.22.1

suse advisories SUSE-SU-2025:3723-1SUSE-SU-2025:03599-1SUSE-SU-2025:02968-1

  • libqt5-qtbase openSUSE Tumbleweed 5.15.17+kde122-2.1

opensuse advisories openSUSE-SU-2025:15240-1

  • qt5-qtbase AlmaLinux 9 5.15.9-11.el9_6
  • qt5-qtbase-gui AlmaLinux 9 5.15.9-11.el9_6
  • qt5-qtbase-odbc AlmaLinux 9 5.15.9-11.el9_6
  • qt5-qtbase-mysql AlmaLinux 9 5.15.9-11.el9_6
  • qt5-qtbase-common AlmaLinux 9 5.15.9-11.el9_6
  • qt5-qtbase-examples AlmaLinux 9 5.15.9-11.el9_6
  • qt5-qtbase-postgresql AlmaLinux 9 5.15.9-11.el9_6
  • qt6-qtbase-common AlmaLinux 10 6.8.1-9.el10_0

almalinux advisories ALSA-2025:9462ALSA-2025:9486

  • qt5-qtbase Rocky Linux 9 5.15.9-11.el9_6
  • qt6-qtbase Rocky Linux 10 6.8.1-9.el10_0

rocky linux advisories RLSA-2025:9462RLSA-2025:9486

  • qtbase Azure Linux 3.0 6.6.3-4
  • qt5-qtbase CBL-Mariner 2.0 5.12.11-18

azure linux advisories AZL-64349AZL-64361

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-5455 updated cvss 5.3

qt6-qtbase: qt5-qtbase: QtCore Assertion Failure Denial of Service

  • Red Hat Enterprise Linux 7 qt5-qtbase, qt5-qtbase-gui, qt5-rpm-macros, qt5-qtbase-odbc, qt5-qtbase-mysql, qt5-qtbase-common, +2 more Red Hat Enterprise Linux 8 qt5-qtbase, qt5-qtbase-gui, qt5-qtbase-odbc, qt5-qtbase-mysql, qt5-qtbase-common, qt5-qtbase-examples, +1 more
    affected: workaround, no fix available “Fix deferred”
  • Red Hat CodeReady Linux Builder EUS (v.9.4) qt5-qtbase-static 5.15.9-11.el9_4, qt5-qtbase-debuginfo 5.15.9-11.el9_4, qt5-qtbase-debugsource 5.15.9-11.el9_4, qt5-qtbase-gui-debuginfo 5.15.9-11.el9_4, qt5-qtbase-odbc-debuginfo 5.15.9-11.el9_4, qt5-qtbase-devel-debuginfo 5.15.9-11.el9_4, +4 more
    fixed: vendor fix RHSA-2025:11841
  • Red Hat Enterprise Linux AppStream (v. 9) qt5-qtbase 5.15.9-11.el9_6, qt5-qtbase-gui 5.15.9-11.el9_6, qt5-qtbase-odbc 5.15.9-11.el9_6, qt5-qtbase-mysql 5.15.9-11.el9_6, qt5-qtbase-common 5.15.9-11.el9_6, qt5-qtbase-examples 5.15.9-11.el9_6, +1 more
    fixed: vendor fix RHSA-2025:9462
  • Red Hat Enterprise Linux AppStream (v. 10) qt6-qtbase 6.8.1-9.el10_0, qt6-qtbase-gui 6.8.1-9.el10_0, qt6-qtbase-odbc 6.8.1-9.el10_0, qt6-qtbase-mysql 6.8.1-9.el10_0, qt6-qtbase-common 6.8.1-9.el10_0, qt6-qtbase-postgresql 6.8.1-9.el10_0
    fixed: vendor fix RHSA-2025:9486
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) qt5-qtbase 5.15.9-11.el9_4, qt5-qtbase-gui 5.15.9-11.el9_4, qt5-qtbase-odbc 5.15.9-11.el9_4, qt5-qtbase-mysql 5.15.9-11.el9_4, qt5-qtbase-common 5.15.9-11.el9_4, qt5-qtbase-examples 5.15.9-11.el9_4, +1 more
    fixed: vendor fix RHSA-2025:11841
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) qt5-qtbase-static 5.15.9-11.el9_6, qt5-qtbase-debuginfo 5.15.9-11.el9_6, qt5-qtbase-debugsource 5.15.9-11.el9_6, qt5-qtbase-gui-debuginfo 5.15.9-11.el9_6, qt5-qtbase-odbc-debuginfo 5.15.9-11.el9_6, qt5-qtbase-devel-debuginfo 5.15.9-11.el9_6, +4 more
    fixed: vendor fix RHSA-2025:9462
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) qt6-qtbase-examples 6.8.1-9.el10_0
    fixed: vendor fix RHSA-2025:9486

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
17 mo ago

Exploit prediction

0.40% chance of exploitation in the next 30 days, higher than 34% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 8.4 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
CNA 4.0 8.4 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

Affected products

  • Qt Qt

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.