CVE-2021-42072

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.7% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-11-08 · updated 2026-06-17
Weakness: CWE-287

Description

An issue was discovered in Barrier before 2.4.0. The barriers component (aka the server-side implementation of Barrier) does not sufficiently verify the identify of connecting clients. Clients can thus exploit weaknesses in the provided protocol to cause denial-of-service or stage further attacks that could lead to information leaks or integrity corruption.

Affected products

Barrier Project Barrier: before 2.4.0 — fixed in 2.4.0
Fedoraproject Fedora: 34, 35

How to fix

Upgrade to a fixed version: Barrier Project Barrier 2.4.0. Check the vendor advisory for mitigations.

References

http://www.openwall.com/lists/oss-security/2021/11/02/4
https://github.com/debauchee/barrier/releases/tag/v2.4.0
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CIEVNCFEFO7L3NTM4VUZB3WKYYCBTFCI/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XMU3STOKHPEZSC54MZ42YBFFC2R3BU2Q/
http://www.openwall.com/lists/oss-security/2021/11/02/4
https://github.com/debauchee/barrier/releases/tag/v2.4.0
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CIEVNCFEFO7L3NTM4VUZB3WKYYCBTFCI/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XMU3STOKHPEZSC54MZ42YBFFC2R3BU2Q/

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