CVE-2022-21716
CVSS v3
7.5
HIGH
EPSS Score
3.5 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 22.2.0, Twisted SSH client and server implement is able to accept an infinite amount of data for the peer's SSH version identifier. This ends up with a buffer using all the available memory. The attach is a simple as `nc -rv localhost 22 < /dev/zero`. A patch is available in version 22.2.0. There are currently no known workarounds.
Technical details
- Published
- 2022-03-03
Frequently asked questions
What is CVE-2022-21716?
Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 22.2.0, Twisted SSH client and server implement is able to accept an infinite amount of data for the peer's SSH version identifier. This ends up with a buffer using all the available memory. The attach is a simple as `nc -rv localhost 22 < /dev/zero`. A patch is available in version 22.2.0. There are currently no known workarounds.
Is CVE-2022-21716 actively exploited?
Active exploitation of CVE-2022-21716 has not been confirmed. Its EPSS score was 3.5% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2022-21716?
CVE-2022-21716 has a CVSS v3 base score of 7.5 (HIGH severity).
Is CVE-2022-21716 affecting your environment?
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