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Public proof of conceptFix available

CVE-2022-21716

A public proof of concept exists; no exploitation attested.

  • Published2022-03-03
  • Fixed in22.2.0
  • WeaknessCWE-120 · CWE-770

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2022-03-0321:15CVE publishedNVD

Versions per branch

NVD · OSV
Twisted
BranchAffectedFixed in
22.2≥ 21.7.0, < 22.2.022.2.0
Fedoraproject fedora
BranchAffectedFixed in
35.x= 35no fix published
36.x= 36no fix published
Oracle http server
BranchAffectedFixed in
12.2= 12.2.1.3.0no fix published
12.2= 12.2.1.4.0no fix published

2 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As GitHub_M, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • twisted
    Affected
    • = < 22.2.0no fix stated

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2023-01-11

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • py3-scrapyCleanStartall versions · fixed in 2.6.1-r0
  • py3-twistedCleanStartall versions · fixed in 22.2.0-r0
  • py3-twistedAlpine:v3.24all versions · fixed in 22.2.0-r0
  • py3-twistedAlpine:v3.23all versions · fixed in 22.2.0-r0
  • py3-twistedAlpine:v3.22all versions · fixed in 22.2.0-r0
  • py3-twistedAlpine:v3.21all versions · fixed in 22.2.0-r0
  • py3-twistedAlpine:v3.20all versions · fixed in 22.2.0-r0
  • py3-twistedAlpine:v3.19all versions · fixed in 22.2.0-r0

42 more package ranges on OSV.dev

Vendor advisories

  • CVE-2022-21716 Red Hat Product Security14 products fixed · 7 known affected

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

    automation-controller.src as a component of Red Hat Ansible Automation Platform 2 · python-twisted-conch.src as a component of Red Hat Enterprise Linux 6 · python-twisted.src as a component of Red Hat Enterprise Linux 6 · +4 more

  • RHSA-2022:0982 Red Hat Product Security7 products fixed

    Red Hat Security Advisory: Red Hat OpenStack Platform 16.1 (python-twisted) security update

  • RHSA-2022:0992 Red Hat Product Security7 products fixed

    Red Hat Security Advisory: Red Hat OpenStack Platform 16.2 (python-twisted) security update

Full record on NVD

Fix

  1. Update Twisted to 22.2.0
  2. Vendor fix Red Hat Product Security RHSA-2022:0982 · 14 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  3. No fix available, says the vendor Red Hat Product Security CVE-2022-21716 · 5 productsAffected
  4. No fix planned, says the vendor Red Hat Product Security CVE-2022-21716 · 2 productsOut of support scope

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • CISA-ADPSSVC decisionpoc2025-04-22
  • CNACVSS 3.17.5known since 2026-10-23
  • NVDCVSS 3.17.5read 2026-10-23
  • NVDCVSS 2.05read 2026-10-23
  • CNAweakness (CWE)CWE-120known since 2026-10-23
  • NVDweakness (CWE)CWE-770read 2026-10-23
  • FIRST EPSSEPSS score3.5 %2026-11-08
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryHIGH2022-03-03

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2022-03-03
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-rv6r-3f5q-9rgx

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?

A proof-of-concept exploit exists for CVE-2022-21716, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2022-21716?

CVE-2022-21716 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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