CVE-2020-20813

Control Channel in OpenVPN 2.4.7 and earlier allows remote attackers to cause a denial of service via crafted reset packet.

Published: 2023-08-22 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-20813 is rated Moderate Risk (47/100): CVSS High severity, with low exploitation likelihood (EPSS 0.69%). 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-2020-20813

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 2026-06-15 0.35% 0.69% +0.34%
2 2026-05-17 0.31% 0.35% +0.04%
3 2026-01-30 — 0.31% —

Full EPSS history (14 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-20813

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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:N)
Doesn’t really leak secrets in a meaningful 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 3.6 [email protected]

Weakness enumeration for CVE-2020-20813

OS Trackers for CVE-2020-20813

vendor priority summary link
alpine high CVE-2020-20813: 1 source package rows (openvpn); 5 state rows across 5 repos (3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 0, open 5. https://security.alpinelinux.org/vuln/CVE-2020-20813
suse medium — https://www.suse.com/security/cve/CVE-2020-20813/
ubuntu medium CVE-2020-20813 medium priority: Ubuntu including 1 source packages (openvpn), 11 status rows across 11 suites (bionic, focal, jammy, lunar, mantic, noble, oracular, plucky, trusty, upstream, xenial): ignored 10, needs-triage 1. https://ubuntu.com/security/CVE-2020-20813

Affected software / configurations for CVE-2020-20813

Vendor Product Version Raw CPE
openvpn openvpn <= 2.4.7 cpe:2.3:a:openvpn:openvpn:*:*:*:*:*:*:*:*

References for CVE-2020-20813

URL Tags
https://www.freebuf.com/vuls/215171.html Third Party Advisory
cvelogic Threat Intelligence