CyberSecBulletin
CVE-2025-0890NVD status: Analyzed

VMG4325-B10A firmware: Insufficiently Protected Credentials

Published Updated By the CyberSecBulletin desk

CVE-2025-0890 is a critical-severity insufficiently protected credentials vulnerability in VMG4325-B10A firmware from Zyxel, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected VMG4325-B10A firmware versions: <= 1.00(AAFR.4)C0_20170615. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 14.3% chance of exploitation within 30 days, which is in the top 3.34% of all scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Check which version of VMG4325-B10A firmware you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on zyxel.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
ZyxelVMG4325-B10A firmware<= 1.00(AAFR.4)C0_20170615Not stated
ZyxelSbg3500-n000 FirmwareNot specified in the recordNot stated
ZyxelVmg1312-b10a FirmwareNot specified in the recordNot stated
ZyxelVmg1312-b10b FirmwareNot specified in the recordNot stated
ZyxelVmg1312-b10e FirmwareNot specified in the recordNot stated
ZyxelVmg3312-b10a FirmwareNot specified in the recordNot stated
ZyxelVmg3313-b10a FirmwareNot specified in the recordNot stated
ZyxelVmg3926-b10b FirmwareNot specified in the recordNot stated
ZyxelVmg4380-b10a FirmwareNot specified in the recordNot stated
ZyxelVmg8324-b10a FirmwareNot specified in the recordNot stated
ZyxelVmg8924-b10a FirmwareNot specified in the recordNot stated
ZyxelSbg3300-n000 FirmwareNot specified in the recordNot stated
ZyxelSbg3300-nb00 FirmwareNot specified in the recordNot stated
ZyxelSbg3500-nb00 FirmwareNot specified in the recordNot stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (zyxel.com.tw).

Official description

**UNSUPPORTED WHEN ASSIGNED** Insecure default credentials for the Telnet function in the legacy DSL CPE Zyxel VMG4325-B10A firmware version 1.00(AAFR.4)C0_20170615 could allow an attacker to log in to the management interface if the administrators have the option to change the default credentials but fail to do so.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Insufficiently Protected Credentials

The product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval.

How developers prevent this class of flaw

  • Use an appropriate security mechanism to protect the credentials.
  • Make appropriate use of cryptography to protect the credentials.
  • Use industry standards to protect the credentials (e.g. LDAP, keystore, etc.).

More Insufficiently Protected Credentials vulnerabilities (CWE-522)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in VMG4325-B10A firmware

All VMG4325-B10A firmware vulnerabilities

Recent Insufficiently Protected Credentials vulnerabilities

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