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CVE-2022-21716

28
FAUCET Score

CVE-2022-21716 is a high-severity denial-of-service vulnerability affecting the Twisted SSH client and server, present in versions prior to 22.2.0, as well as various distributions like Debian, Fedora, and Oracle. The flaw allows an unauthenticated attacker to exhaust all available memory by sending an infinite amount of data as the SSH version identifier, leading to a system crash. With a CVSS score of 7.5, this vulnerability is easily exploitable over the network with low attack complexity and no user interaction required, resulting in a complete loss of availability. While there are no known workarounds, a patch is available in Twisted version 22.2.0. There is currently no evidence of active exploitation, no public exploit code (Metasploit, Nuclei, ExploitDB), and limited community discussion, suggesting low current exploitability.

Impacted Technologies

VendorProductVersion(s)CPE
>= 21.7.0, < 22.2.0CPE matchmatch criteria
cpe:2.3:a:twisted:twisted:*:*:*:*:*:*:*:*
9.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
12.2.1.3.0CPE matchmatch criteria
cpe:2.3:a:oracle:http_server:12.2.1.3.0:*:*:*:*:*:*:*
12.2.1.4.0CPE matchmatch criteria
cpe:2.3:a:oracle:http_server:12.2.1.4.0:*:*:*:*:*:*:*
8.8CPE matchmatch criteria
cpe:2.3:a:oracle:zfs_storage_appliance_kit:8.8:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
3.51%
Probability of exploitation in next 30 days
EPSS Percentile
88.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0351 is in the 79th percentile among its peer group of 51,485 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (9)

github_advisorypatch availablevia nvd_reference
View patch
oraclepatch availablevia nvd_reference
View patch
pippatch availablevia ghsa
Product: twistedFixed in: 22.2.0
redhatpatch availablevia redhat_api
Product: Red Hat OpenStack Platform 16.2Fixed in: python-twisted-0:16.4.1-19.el8ost
View patch
redhatpatch availablevia redhat_api
Product: Red Hat OpenStack Platform 16.1Fixed in: python-twisted-0:16.4.1-19.el8ost
View patch
redhatno patchvia redhat_api
Product: Red Hat Ansible Automation Platform 2Fixed in: automation-controller
redhatno patchvia redhat_api
Product: Red Hat OpenStack Platform 13 (Queens)Fixed in: python-twisted
redhatno patchvia redhat_api
Product: Red Hat Satellite 6Fixed in: python-twisted
redhatno patchvia redhat_api
Product: Service Telemetry Framework 1.3 for RHEL 8Fixed in: python-twisted

Vendor Advisories (2)

pipGHSA-rv6r-3f5q-9rgxhigh

Twisted SSH client and server deny of service during SSH handshake.

Mar 3, 2022
redhatCVE-2022-21716Important

python-twisted: SSH client and server denial of service during SSH handshake

Mar 3, 2022

References

github.com / twisted/twisted/commit/89c395ee794e85a9657b112c4351417850330ef9
PatchThird Party Advisory
github.com / twisted/twisted/releases/tag/twisted-22.2.0
Release NotesThird Party Advisory
github.com / twisted/twisted/security/advisories/GHSA-rv6r-3f5q-9rgx
ExploitPatchThird Party Advisory
lists.debian.org / debian-lts-announce/2022/03/msg00009.html
Mailing ListThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/7U6KYDTOLPICAVSR34G2WRYLFBD2YW5K
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/GLKHA6WREIVAMBQD7KKWYHPHGGNKMAG6
security.gentoo.org / glsa/202301-02
Third Party Advisory
twistedmatrix.com / trac/ticket/10284
Issue TrackingVendor Advisory
oracle.com / security-alerts/cpuapr2022.html
PatchThird Party Advisory