CVE-2020-6991Network attack vector

Unauthenticated device access via weak password requirements

Published Mar 24, 2020 · Updated Aug 4, 2024

Weak password requirements in Moxa EDS-G516E Series firmware 5.2 and earlier allow remote attackers to gain device access. The firmware's account policy accepts passwords that do not meet adequate strength requirements; Moxa does not publish the exact acceptance rules. A reachable management login and a guessable account password are required, and repeated guesses can yield that account's device access unless login-failure lockout is enabled.

CVSS severity9.8
Critical
EPSS probability1.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Weak password requirements in Moxa EDS-G516E Series firmware 5.2 and earlier allow remote attackers to gain device access. The firmware's account policy accepts passwords that do not meet adequate strength requirements; Moxa does not publish the exact acceptance rules. A reachable management login and a guessable account password are required, and repeated guesses can yield that account's device access unless login-failure lockout is enabled.

The record

CVE
CVE-2020-6991
Published
Mar 24, 2020
Updated
Aug 4, 2024
Vendor
Moxa
Product
EDS-G516E Series
Classifications
CWE-521, T1110.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 24, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Moxa EDS-G516E Series firmware, Version 5.2 or lower

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Moxa · EDS-G516E Seriesversion=Moxa EDS-G516E Series firmware, Version 5.2 or lower

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:N
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-521Weak Password Requirements
T1110.001Brute Force: Password Guessing

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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