CVE-2019-18281

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2019-10-23 · updated 2026-06-17
Weakness: CWE-119

Description

An out-of-bounds memory access in the generateDirectionalRuns() function in qtextengine.cpp in Qt qtbase 5.11.x and 5.12.x before 5.12.5 allows attackers to cause a denial of service by crashing an application via a text file containing many directional characters.

Affected products

Debian Linux: 9.0, 10.0
Qtbase: from 5.11.0 through 5.11.3; from 5.12.0 before 5.12.5 — fixed in 5.12.5

How to fix

Upgrade to a fixed version: Qtbase 5.12.5. Check the vendor advisory for mitigations.

References

https://bugreports.qt.io/browse/QTBUG-77819
https://bugs.launchpad.net/ubuntu/+source/qtbase-opensource-src/+bug/1848784
https://codereview.qt-project.org/c/qt/qtbase/+/271889
https://seclists.org/bugtraq/2019/Nov/4
https://security.gentoo.org/glsa/202003-60
https://usn.ubuntu.com/4275-1/
https://www.debian.org/security/2019/dsa-4556
https://bugreports.qt.io/browse/QTBUG-77819
https://bugs.launchpad.net/ubuntu/+source/qtbase-opensource-src/+bug/1848784
https://codereview.qt-project.org/c/qt/qtbase/+/271889
https://seclists.org/bugtraq/2019/Nov/4
https://security.gentoo.org/glsa/202003-60

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