CVE-2020-27222Network attack vector

Denial of service via persistent DTLS selector state

Published Feb 3, 2021 · Updated Aug 4, 2024

Denial of service in Eclipse Californium 2.3.0 through 2.6.0 allows remote attackers to halt certificate-based DTLS handshakes. The Scandium DefaultCipherSuiteSelector stores a failed certificate-support check in an instance field, so one mismatched handshake disables certificate cipher selection for later clients. A remote client needs only to cause a TLS-parameter mismatch; affected servers reject later X.509 and RPK handshakes until restart.

CVSS severity7.5
High
EPSS probability0.85%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Eclipse Californium 2.3.0 through 2.6.0 allows remote attackers to halt certificate-based DTLS handshakes. The Scandium DefaultCipherSuiteSelector stores a failed certificate-support check in an instance field, so one mismatched handshake disables certificate cipher selection for later clients. A remote client needs only to cause a TLS-parameter mismatch; affected servers reject later X.509 and RPK handshakes until restart.

The record

CVE
CVE-2020-27222
Published
Feb 3, 2021
Updated
Aug 4, 2024
Vendor
The Eclipse Foundation
Product
Eclipse Californium
Classifications
CWE-372, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 3, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=[2.3.0, 2.6.0]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Eclipse Foundation · Eclipse Californiumversion=[2.3.0, 2.6.0]

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-372Incomplete Internal State Distinction
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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