What’s Vulnerable › Vulnerabilities

CVE-2021-45079

• Severity: critical (CVSS 9.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2022-01-31 · updated 2026-06-17
• Weakness: CWE-476

Description

In strongSwan before 5.9.5, a malicious responder can send an EAP-Success message too early without actually authenticating the client and (in the case of EAP methods with mutual authentication and EAP-only authentication for IKEv2) even without server authentication.

Affected products

• Canonical Ubuntu Linux: 14.04, 16.04, 18.04, 20.04, 21.10
• Debian Linux: 9.0, 10.0, 11.0
• Fedoraproject Extra Packages For Enterprise Linux: 7.0, 8.0, 9.0
• Fedoraproject Fedora: 34, 35
• strongSwan: from 4.1.2 before 5.9.5 — fixed in 5.9.5

How to fix

Upgrade to a fixed version: strongSwan 5.9.5. Check the vendor advisory for mitigations.

References

• https://www.strongswan.org/blog/2022/01/24/strongswan-vulnerability-%28cve-2021-45079%29.html
• https://www.strongswan.org/blog/2022/01/24/strongswan-vulnerability-%28cve-2021-45079%29.html

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