CVE-2021-20206

An improper limitation of path name flaw was found in containernetworking/cni in versions before 0.8.1. When specifying the plugin to load in the 'type' field in the network configuration, it is possible to use special elements such as "../" separators to reference binaries elsewhere on the system. This flaw allows an attacker to execute other existing binaries other than the cni plugins/types, such as 'reboot'. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.

Published: 2021-03-26 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-20206 is rated Moderate Risk (55.2/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.52%). EPSS rose +1.40% over the last day, indicating growing attacker interest. 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-2021-20206

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 0.12% 1.52% +1.40%
2 2025-11-21 0.69% 0.12% -0.57%
3 2025-11-18 — 0.69% —

Full EPSS history (14 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-20206

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.2 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/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:H)
They need powerful rights—admin, root, or similar—before this pays off.
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:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.2 5.9 [email protected]
6.5 2.0 MEDIUM
AV:N/AC:L/Au:S/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.0 6.4 [email protected]

Weakness enumeration for CVE-2021-20206

GitHub Security Advisory for CVE-2021-20206

GHSA-xjqr-g762-pxwp · Severity: high · Ecosystem: go — containernetworking/cni improper limitation of path name

OS Trackers for CVE-2021-20206

vendor priority summary link
alpine high CVE-2021-20206: 1 source package rows (buildah); 7 state rows across 7 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 7, open 0. https://security.alpinelinux.org/vuln/CVE-2021-20206
debian not yet assigned CVE-2021-20206 not yet assigned priority: Debian including 1 source packages (golang-github-appc-cni), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-20206
redhat medium — https://access.redhat.com/security/cve/CVE-2021-20206
suse high CVE-2021-20206 severity important: SUSE including 55 source package names (buildah, buildah-1.23.0-1.1, …), 80 product×package rows across 30 product lines (SUSE CaaS Platform 4.0, SUSE Enterprise Storage 6, … (30 product lines)): Fixed 73, Known Not Affected 7. https://www.suse.com/security/cve/CVE-2021-20206/
ubuntu medium CVE-2021-20206 medium priority: Ubuntu including 1 source packages (golang-github-appc-cni), 16 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): ignored 8, needs-triage 6, DNE 2. https://ubuntu.com/security/CVE-2021-20206

Affected software / configurations for CVE-2021-20206

Vendor Product Version Raw CPE
linuxfoundation container_network_interface < 0.8.1 cpe:2.3:a:linuxfoundation:container_network_interface:*:*:*:*:*:*:*:*

References for CVE-2021-20206

cvelogic Threat Intelligence