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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Qt | Qt | ≤ 5.15.18, 6.0.0 – ≤ 6.5.8, 6.6.0 – ≤ 6.8.3, 6.9.0 | 6.5.9 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | qt6-base | 6.8.2+dfsg-8 | — |
| Debian 14 | qtbase-opensource-src | 5.15.15+dfsg-6 | — |
| Debian 13 | qt6-base | 6.8.2+dfsg-8 | — |
| Debian 13 | qtbase-opensource-src | 5.15.15+dfsg-6 | — |
| Debian 12 | qt6-base +1 | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | qt6-base +1 | No fix yet | — |
| Ubuntu 26.04 LTS | qtbase-opensource-src-gles | No fix yet | — |
| Ubuntu 25.10 | qt6-base +1 | No fix yet | — |
| Ubuntu 24.04 LTS | qt6-base +2 | No fix yet | — |
| Ubuntu 22.04 LTS | qt6-base +2 | No fix yet | — |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | qtbase-opensource-src-gles | No fix yet | — |
| Ubuntu 16.04 LTS | qtbase-opensource-src-gles | No fix yet | — |
| Ubuntu Pro 20.04 LTS | qtbase-opensource-src | No fix yet | — |
| Ubuntu Pro 18.04 LTS | qtbase-opensource-src | No fix yet | — |
| Ubuntu Pro 16.04 LTS | qtbase-opensource-src | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | qt6-qtbase +9 | 6.8.1-9.el10_0 | RHSA-2025:9486 |
| RHEL 9 | qt5-qtbase +9 | 5.15.9-11.el9_6 | RHSA-2025:9462 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 9.4 EUS | qt5-qtbase +9 | 5.15.9-11.el9_4 | RHSA-2025:11841 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | qt6-qtbase-common | 6.8.1-9.el10_0 | ALSA-2025:9486 |
| AlmaLinux 9 | qt5-qtbase +9 | 5.15.9-11.el9_6 | ALSA-2025:9462 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | qt6-qtbase | 6.8.1-9.el10_0 | RLSA-2025:9486 |
| Rocky Linux 9 | qt5-qtbase | 5.15.9-11.el9_6 | RLSA-2025:9462 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | libqt5-qtbase | 5.15.12+kde151-150600.3.9.1 | SUSE-SU-2025:3723-1 |
| SLES 15 SP7 | qt6-base +1 | 6.6.3-150600.3.6.1 | SUSE-SU-2025:03599-1 |
| SLES 15 SP6 | libqt5-qtbase | 5.15.12+kde151-150600.3.9.1 | SUSE-SU-2025:3723-1 |
| SLES 15 SP6 | qt6-base +1 | 6.6.3-150600.3.6.1 | SUSE-SU-2025:03599-1 |
| SLES 12 SP5 | libqt4 +2 | 4.8.7-8.22.1 | SUSE-SU-2025:02968-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | libqt5-qtbase | 5.15.17+kde122-2.1 | openSUSE-SU-2025:15240-1 |
| openSUSE Leap 15.6 | libqt5-qtbase | 5.15.12+kde151-150600.3.9.1 | SUSE-SU-2025:3723-1 |
| openSUSE Leap 15.6 | qt6-base +1 | 6.6.3-150600.3.6.1 | SUSE-SU-2025:03599-1 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | qtbase | 6.6.3-4 | — |
| Azure Linux 2 (CBL-Mariner) | qt5-qtbase | 5.12.11-18 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | qt6-qtbase +9 | 6.8.1-9.el10_0 | ELSA-2025-9486 |
| Oracle Linux 9 | qt5-qtbase +9 | 5.15.9-11.el9_6 | ELSA-2025-9462 |
Advisories 14
- ALSA-2025:9462 Moderate: qt5-qtbase security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2025:9486 Moderate: qt6-qtbase security update AlmaLinux Security Advisories · Oct 29, 2026
- RHSA-2025:9486 Red Hat Security Advisory: qt6-qtbase security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:9462 Red Hat Security Advisory: qt5-qtbase security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2025:11841 Red Hat Security Advisory: qt5-qtbase security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- openSUSE-SU-2025:15240-1 libQt5Bootstrap-devel-static-32bit-5.15.17+kde122-2.1 on GA media SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:03599-1 Security update for qt6-base SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:3723-1 Security update for libqt5-qtbase SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2025:02968-1 Security update for libqt4 SUSE / openSUSE Security Updates · Feb 4, 2026
- WID-SEC-2025-1220 QT: Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Oct 22, 2025
- RLSA-2025:9462 Moderate: qt5-qtbase security update Rocky Linux Security Advisories · Oct 7, 2025
- RLSA-2025:9486 Moderate: qt6-qtbase security update Rocky Linux Security Advisories · Oct 3, 2025
- ELSA-2025-9486 Moderate: qt6-qtbase security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Jun 30, 2025
- ELSA-2025-9462 Moderate: qt5-qtbase security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jun 24, 2025