CVE catalog

CVE-2018-21035

qtwebsockets-opensource-src: CVE-2018-21035

Severity: High · CVSS 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: Sep 23, 2018, 12:00:00 AM UTC
Source: [NVD] · [CVE record]
EPSS: 2.34% · Oct 25, 2026

In Qt through 5.14.1, the WebSocket implementation accepts up to 2GB for frames and 2GB for messages. Smaller limits cannot be configured. This makes it easier for attackers to cause a denial of service (memory consumption).

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	qtwebsockets-opensource-src	sid	`5.15.19-2`	fixed
Debian	qtwebsockets-opensource-src	forky	`5.15.19-2`	fixed
Debian	qtwebsockets-opensource-src	trixie	`5.15.15-2`	fixed
Debian	qtwebsockets-opensource-src	bookworm	`5.15.8-2`	fixed
Ubuntu	qtwebsockets-opensource-src	16.04	`5.4.2-2build1`	vulnerable
Ubuntu	qtwebsockets-opensource-src	16.04	`5.5.1-4build1`	vulnerable
Ubuntu	qtwebsockets-opensource-src	18.04	`5.9.1-3`	vulnerable
Ubuntu	qtwebsockets-opensource-src	18.04	`5.9.2-3build1`	vulnerable
Ubuntu	qtwebsockets-opensource-src	18.04	`5.9.3-0ubuntu1`	vulnerable
Ubuntu	qtwebsockets-opensource-src	18.04	`5.9.4-0ubuntu1`	vulnerable
Ubuntu	qtwebsockets-opensource-src	18.04	`5.9.5-0ubuntu1`	vulnerable
Ubuntu	qtwebsockets-opensource-src	20.04	`5.12.4-1`	vulnerable
Ubuntu	qtwebsockets-opensource-src	20.04	`5.12.5-2`	vulnerable
Ubuntu	qtwebsockets-opensource-src	20.04	`5.12.5-2build1`	vulnerable
Ubuntu	qtwebsockets-opensource-src	20.04	`5.12.8-0ubuntu1`	vulnerable

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	qtwebsockets-opensource-src	source	sid	`5.15.1-2`	low	Not reported	[953049]
Debian	qtwebsockets-opensource-src	source	forky	`5.15.1-2`	low	Not reported	[953049]
Debian	qtwebsockets-opensource-src	source	trixie	`5.15.1-2`	low	Not reported	[953049]
Debian	qtwebsockets-opensource-src	source	bookworm	`5.15.1-2`	low	Not reported	[953049]

[Debian bug #953049]

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[libqt5websockets5]Fixed
Source package: [qtwebsockets-opensource-src]
Details (2)
- 5.15.8-2 · amd64 · bookworm
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · bookworm; dsa · qtwebsockets-opensource-src · debian · 12
- 5.15.8-2 · arm64 · bookworm
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · bookworm; dsa · qtwebsockets-opensource-src · debian · 12
[libqt5websockets5-dev]Fixed
Source package: [qtwebsockets-opensource-src]
Details (2)
- 5.15.8-2 · amd64 · bookworm
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · bookworm; dsa · qtwebsockets-opensource-src · debian · 12
- 5.15.8-2 · arm64 · bookworm
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · bookworm; dsa · qtwebsockets-opensource-src · debian · 12
[qml-module-qt-websockets]Fixed
Source package: [qtwebsockets-opensource-src]
Details (2)
- 5.15.8-2 · amd64 · bookworm
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · bookworm; dsa · qtwebsockets-opensource-src · debian · 12
- 5.15.8-2 · arm64 · bookworm
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · bookworm; dsa · qtwebsockets-opensource-src · debian · 12
[qml-module-qtwebsockets]Fixed
Source package: [qtwebsockets-opensource-src]
Details (2)
- 5.15.8-2 · amd64 · bookworm
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · bookworm; dsa · qtwebsockets-opensource-src · debian · 12
- 5.15.8-2 · arm64 · bookworm
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · bookworm; dsa · qtwebsockets-opensource-src · debian · 12
[qtwebsockets5-doc]Fixed
Source package: [qtwebsockets-opensource-src]
Details (2)
- 5.15.8-2 · all · bookworm
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · bookworm; dsa · qtwebsockets-opensource-src · debian · 12
- 5.15.8-2 · all · bookworm
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · bookworm; dsa · qtwebsockets-opensource-src · debian · 12
[qtwebsockets5-doc-html]Fixed
Source package: [qtwebsockets-opensource-src]
Details (2)
- 5.15.8-2 · all · bookworm
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · bookworm; dsa · qtwebsockets-opensource-src · debian · 12
- 5.15.8-2 · all · bookworm
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · bookworm; dsa · qtwebsockets-opensource-src · debian · 12
[qtwebsockets5-examples]Fixed
Source package: [qtwebsockets-opensource-src]
Details (2)
- 5.15.8-2 · amd64 · bookworm
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · bookworm; dsa · qtwebsockets-opensource-src · debian · 12
- 5.15.8-2 · arm64 · bookworm
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · bookworm; dsa · qtwebsockets-opensource-src · debian · 12

[Debian 13 (Trixie)]

[libqt5websockets5]Fixed
Source package: [qtwebsockets-opensource-src]
Details (2)
- 5.15.15-2 · amd64 · trixie
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · 13
- 5.15.15-2 · arm64 · trixie
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · 13
[libqt5websockets5-dev]Fixed
Source package: [qtwebsockets-opensource-src]
Details (2)
- 5.15.15-2 · amd64 · trixie
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · 13
- 5.15.15-2 · arm64 · trixie
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · 13
[qml-module-qt-websockets]Fixed
Source package: [qtwebsockets-opensource-src]
Details (2)
- 5.15.15-2 · amd64 · trixie
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · 13
- 5.15.15-2 · arm64 · trixie
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · 13
[qml-module-qtwebsockets]Fixed
Source package: [qtwebsockets-opensource-src]
Details (2)
- 5.15.15-2 · amd64 · trixie
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · 13
- 5.15.15-2 · arm64 · trixie
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · 13
[qtwebsockets5-doc]Fixed
Source package: [qtwebsockets-opensource-src]
Details (2)
- 5.15.15-2 · all · trixie
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · 13
- 5.15.15-2 · all · trixie
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · 13
[qtwebsockets5-doc-html]Fixed
Source package: [qtwebsockets-opensource-src]
Details (2)
- 5.15.15-2 · all · trixie
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · 13
- 5.15.15-2 · all · trixie
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · 13
[qtwebsockets5-examples]Fixed
Source package: [qtwebsockets-opensource-src]
Details (2)
- 5.15.15-2 · amd64 · trixie
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · 13
- 5.15.15-2 · arm64 · trixie
  Fixed · Fixed: 5.15.1-2
  dsa · qtwebsockets-opensource-src · debian · 13

Observed: Oct 23, 2026, 5:36:20 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]