CVE-2021-45079

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.

Published: 2022-01-31 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-45079 is rated Moderate Risk (46/100): CVSS Critical severity, with low exploitation likelihood (EPSS 0.10%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-45079

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-11-21 0.58% 0.10% -0.48%
2 2025-11-18 0.08% 0.58% +0.51%
3 2025-06-13 — 0.08% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-45079

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.1 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.2 [email protected]
5.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 4.9 [email protected]

Weakness enumeration for CVE-2021-45079

OS Trackers for CVE-2021-45079

vendor priority summary link
alpine critical CVE-2021-45079: 1 source package rows (strongswan); 33 state rows across 8 repos (3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 7, open 26. https://security.alpinelinux.org/vuln/CVE-2021-45079
debian not yet assigned CVE-2021-45079 not yet assigned priority: Debian including 1 source packages (strongswan), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-45079
gentoo normal CVE-2021-45079: 1 GLSA(s) (202405-08), 1 atom(s) (net-vpn/strongswan); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-45079
suse medium CVE-2021-45079 severity moderate: SUSE including 56 source package names (strongswan-4.4.0-6.36.12.1, strongswan-5.1.3-26.20.1, …), 244 product×package rows across 52 product lines (HPE Helion OpenStack 8, SUSE CaaS Platform 4.0, … (52 product lines)): Fixed 244. https://www.suse.com/security/cve/CVE-2021-45079/
ubuntu medium CVE-2021-45079 medium priority: Ubuntu including 1 source packages (strongswan), 15 status rows across 15 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): released 14, ignored 1. https://ubuntu.com/security/CVE-2021-45079

Affected software / configurations for CVE-2021-45079

Vendor Product Version Raw CPE
strongswan strongswan >= 4.1.2, < 5.9.5 cpe:2.3:a:strongswan:strongswan:*:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
fedoraproject extra_packages_for_enterprise_linux 7.0 cpe:2.3:a:fedoraproject:extra_packages_for_enterprise_linux:7.0:*:*:*:*:*:*:*
fedoraproject extra_packages_for_enterprise_linux 8.0 cpe:2.3:a:fedoraproject:extra_packages_for_enterprise_linux:8.0:*:*:*:*:*:*:*
fedoraproject extra_packages_for_enterprise_linux 9.0 cpe:2.3:a:fedoraproject:extra_packages_for_enterprise_linux:9.0:*:*:*:*:*:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
fedoraproject fedora 35 cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
canonical ubuntu_linux 14.04 cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:esm:*:*:*
canonical ubuntu_linux 16.04 cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:*
canonical ubuntu_linux 18.04 cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 20.04 cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 21.10 cpe:2.3:o:canonical:ubuntu_linux:21.10:*:*:*:*:*:*:*

References for CVE-2021-45079

cvelogic Threat Intelligence