CVE-2018-21035
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
02 Description
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
03 Exploitation and scoring
- Exploitation
- Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
- SSVC decision
- Not assessed by CISA
- EPSS probability
- 2.33% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 83.1% of scored records. A rank, not a probability.
- NVD base score
- 7.5 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- NVD analysis status
- Modified. NVD last modified this record on 2026-06-17.
- Red Hat severity
- Moderate. Red Hat's rating for its own products, not a CVSS rating.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2020-02-28 19:17Z6 YR AGO
- Last updated
- 2024-08-05 12:19Z2 YR AGO
- Reserved
- 2020-02-28
- Assigning CNA
- mitre
- Record state
- PUBLISHED
- Severity
- High (CVSS 8.6)
- CNA CVSS vector
- CVSS:3.0/AC:L/AV:N/A:H/C:N/I:N/PR:N/S:C/UI:N
- Weaknesses
- Data version
- 5.1
- Document digest
- e879fb1a1d801e2aa235cc88dada92be1ba2624f521d1afefabcbb45cf2be679
05 Affected products
06 References
- codereview.qt-project.orghttps://codereview.qt-project.org/c/qt/qtwebsockets/+/284735
- bugreports.qt.iohttps://bugreports.qt.io/browse/QTBUG-70693
07 Fixed in
AlmaLinux 8
- qt5-qtbase-static Fixed in 5.12.5-6.el8
- qt5-qttools-static Fixed in 5.12.5-2.el8
Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
CloudLinux 8
- qt5-qtbase-static Fixed in 5.12.5-6.el8
- qt5-qttools-static Fixed in 5.12.5-2.el8
Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.
Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
Debian 12
- qtwebsockets-opensource-src Fixed in 5.15.1-2
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 13
- qtwebsockets-opensource-src Fixed in 5.15.1-2
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 14
- qtwebsockets-opensource-src Fixed in 5.15.1-2
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 16.04 LTS
- qtwebsockets-opensource-src No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 18.04 LTS
- qtwebsockets-opensource-src No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 20.04 LTS
- qtwebsockets-opensource-src No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.