CVE-2021-42074

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.8% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-11-08 · updated 2026-06-17
Weakness: CWE-416

Description

An issue was discovered in Barrier before 2.3.4. An unauthenticated attacker can cause a segmentation fault in the barriers component (aka the server-side implementation of Barrier) by quickly opening and closing TCP connections while sending a Hello message for each TCP session.

Affected products

Barrier Project Barrier: before 2.3.4 — fixed in 2.3.4

How to fix

Upgrade to a fixed version: Barrier Project Barrier 2.3.4. 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/v2.3.4
http://www.openwall.com/lists/oss-security/2021/11/02/4
https://github.com/debauchee/barrier/releases/tag/v2.3.4

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