CVE-2025-0890Network attack vector

Management access via unchanged Telnet credentials

Published Feb 4, 2025 · Updated Feb 12, 2025

Insecure default credentials in Zyxel VMG4325-B10A firmware 1.00(AAFR.4)C0_20170615 allow remote attackers to access Telnet management. The Telnet service accepts the factory-set credentials when administrators leave them unchanged, granting an authenticated management session. Exploitation requires Telnet to be enabled and reachable; both Telnet and WAN access are disabled by default, limiting exposure to enabled interfaces retaining the defaults.

CVSS severity9.8
Critical
EPSS probability13.54%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insecure default credentials in Zyxel VMG4325-B10A firmware 1.00(AAFR.4)C0_20170615 allow remote attackers to access Telnet management. The Telnet service accepts the factory-set credentials when administrators leave them unchanged, granting an authenticated management session. Exploitation requires Telnet to be enabled and reachable; both Telnet and WAN access are disabled by default, limiting exposure to enabled interfaces retaining the defaults.

The record

CVE
CVE-2025-0890
Published
Feb 4, 2025
Updated
Feb 12, 2025
Vendor
Zyxel Networks
Product
VMG4325-B10A firmware
Classifications
CWE-287, T1078.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 4, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 12, 2025Record 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=<= 1.00(AAFR.4)C0_20170615

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zyxel Networks · VMG4325-B10A firmwareversion=<= 1.00(AAFR.4)C0_20170615

Published CVSS scores

9.8Zyxel CorporationCVSS: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-287Improper Authentication
T1078.001Default Accounts

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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