What is the CVSS score of CVE-2020-29299?

CVE-2020-29299 has a CVSS 3.1 base score of 7.2 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 2.3%.

Zld CVE-2020-29299

HIGH

Command Injection (CWE-77)

2020-12-27 cve@mitre.org

Command Injection Zyxel Zld Vpn Orchestrator Nsg Firmware Usg Flex Firmware

7.2

CVSS 3.1 · NVD

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Vulnerability Assessment

Weakness	CWE CWE-77 OWASP Top 10:2025 A05:2025 - Injection ASVS 5.0 V1 - Encoding and Sanitization Command injection prevention MITRE ATT&CK 1 technique across 1 tactic: Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Impact	CVSS score of 7.2 (HIGH). Attack characteristics: network attack vector, low complexity, high privileges required, no user interaction not required.
Exploit ScenarioDerived	A remote attacker could inject arbitrary commands into system command execution by sending crafted requests to the affected application.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

No patch listed yet 2.3% exploitation probability (EPSS)

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AnalysisAI

Certain Zyxel products allow command injection by an admin via an input string to chg_exp_pwd during a password-change action. Rated high severity (CVSS 7.2), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Use parameterized APIs, avoid shell execution, validate input with strict allowlists.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Command Injection (CWE-77), which allows attackers to inject arbitrary commands into system command execution. Certain Zyxel products allow command injection by an admin via an input string to chg_exp_pwd during a password-change action. This affects VPN On-premise before ZLD V4.39 week38, VPN Orchestrator before SD-OS V10.03 week32, USG before ZLD V4.39 week38, USG FLEX before ZLD V4.55 week38, ATP before ZLD V4.55 week38, and NSG before 1.33 patch 4. Affected products include: Zyxel Vpn Orchestrator, Zyxel Zld, Zyxel Nsg Firmware, Zyxel Usg Flex Firmware. Version information: before 1.33.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 7.2 HIGH

AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

DescriptionNVD

Certain Zyxel products allow command injection by an admin via an input string to chg_exp_pwd during a password-change action. This affects VPN On-premise before ZLD V4.39 week38, VPN Orchestrator before SD-OS V10.03 week32, USG before ZLD V4.39 week38, USG FLEX before ZLD V4.55 week38, ATP before ZLD V4.55 week38, and NSG before 1.33 patch 4.

Threat Intelligence Overview

EPSS Score

2.3%

Top 18% exploitable

Data Quality

2 sources

Confidence: Low

NVD

CVE.org

EPSS

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity HIGH

CISA KEV No

Public POC No

EPSS 2.3%

Patch available No

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

None

System Exposure· derived

Open

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +2

CVSS: +36

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

OS Command Injection CRITICAL

OS command injection occurs when an application passes unsanitized user input directly into system shell commands.

Affected Products (CPE)NVD

cpe:2.3:o:zyxel:vpn_orchestrator:*:*:*:*:*:*:*:*

cpe:2.3:o:zyxel:zld:*:*:*:*:*:*:*:*

cpe:2.3:o:zyxel:nsg_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:zyxel:nsg_firmware:1.33:-:*:*:*:*:*:*

cpe:2.3:o:zyxel:nsg_firmware:1.33:patch1:*:*:*:*:*:*

cpe:2.3:o:zyxel:usg_flex_firmware:-:*:*:*:*:*:*:*

cpe:2.3:o:zyxel:zld:*:*:*:*:*:*:*:*

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Same weakness CWE-77 – Command Injection

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CVE-2024-21887 CRITICAL POC

9.1

CVE-2016-3081 HIGH POC

8.1

CVE-2012-1823 CRITICAL POC

9.8

CVE-2016-1555 CRITICAL POC

9.8

CVE-2024-55956 CRITICAL POC

9.8

CVE-2015-2051 HIGH POC

8.8

CVE-2017-6327 HIGH POC

8.8

CVE-2023-34960 CRITICAL POC

9.8

Same technique Command Injection

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CVE-2019-15107 CRITICAL POC

9.8

CVE-2024-51378 CRITICAL POC

9.8

CVE-2014-6271 CRITICAL POC

9.8

References

Advisories & patches

ADVISORY https://www.zyxel.com/support/Zyxel-security-advisory-for-command-injection-vulnerability-of-firewalls.shtml ADVISORY https://www.zyxel.com/us/en/support/security_advisories.shtml

Search Externally

GitHub PoC

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