CVE-2019-18281

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.

Published: 2019-10-23 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2019-18281 is rated Moderate Risk (45/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 2.05%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2019-18281

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 1.75% 2.05% +0.30%
2 2025-11-21 1.58% 1.75% +0.17%
3 2025-11-18 — 1.58% —

Full EPSS history (20 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2019-18281

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 2.8 1.4 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2019-18281

OS Trackers for CVE-2019-18281

vendor priority summary link
debian not yet assigned CVE-2019-18281 not yet assigned priority: Debian including 2 source packages (qtbase-opensource-src, qtbase-opensource-src-gles), 10 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 10. https://security-tracker.debian.org/tracker/CVE-2019-18281
gentoo normal CVE-2019-18281: 1 GLSA(s) (202003-60), 1 atom(s) (dev-qt/qtcore); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2019-18281
redhat low — https://access.redhat.com/security/cve/CVE-2019-18281
ubuntu medium CVE-2019-18281 medium priority: Ubuntu including 1 source packages (qtbase-opensource-src), 6 status rows across 6 suites (bionic, disco, eoan, trusty, upstream, xenial): not-affected 2, released 2, DNE 1, ignored 1. https://ubuntu.com/security/CVE-2019-18281

Affected software / configurations for CVE-2019-18281

Vendor Product Version Raw CPE
qt qtbase >= 5.11.0, <= 5.11.3 cpe:2.3:a:qt:qtbase:*:*:*:*:*:*:*:*
qt qtbase >= 5.12.0, < 5.12.5 cpe:2.3:a:qt:qtbase:*:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

References for CVE-2019-18281

cvelogic Threat Intelligence