CVE-2018-21035
CVSS v3
7.5
HIGH
EPSS Score
2.3 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
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).
Technical details
- Published
- 2020-02-28
Frequently asked questions
What is 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 service (memory consumption).
Is CVE-2018-21035 actively exploited?
Active exploitation of CVE-2018-21035 has not been confirmed. Its EPSS score was 2.3% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2018-21035?
CVE-2018-21035 has a CVSS v3 base score of 7.5 (HIGH severity).
Is CVE-2018-21035 affecting your environment?
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