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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.…
- 8.6HighCVSS base score
- 2.3%Exploitation in 30 daysEPSS · top 16% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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 service (memory consumption).
Timeline
ID reserved
By mitre
Published
- 4 years later
· 4 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| mitreCNA (assigner) | 3.0 | High8.6 | CVSS:3.0/AC:L/AV:N/A:H/C:N/I:N/PR:N/S:C/UI:N |
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 2.3% · top 16% of all CVEs (9 Nov 2026)
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.6.
Affected products
n/a
- affected n/a
References
2
- https://codereview.qt-project.org/c/qt/qtwebsockets/+/284735 (opens in a new tab)x_refsource_MISCx_transferred
- https://bugreports.qt.io/browse/QTBUG-70693 (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2018-13555 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2018-21035)Record last updated .