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Nbg7510 FirmwareOperating system · Zyxel

CVE-2022-38546

CRITICAL · 9.8 CVSS v3.1 Published 2022-12-21
Fix available
A fix is available. Upgrade to after 1.00 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A DNS misconfiguration was found in Zyxel NBG7510 firmware versions prior to V1.00(ABZY.3)C0, which could allow an unauthenticated attacker to access the DNS server when the device is switched to the AP mode.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A DNS misconfiguration in Zyxel NBG7510 routers allows unauthenticated network attackers to access the DNS server when the device operates in AP (Access Point) mode. This critical vulnerability (CVSS 9.8) stems from improper access control on the DNS service, potentially enabling DNS hijacking or redirection attacks against connected clients.

MitigationUpdate the device firmware to version V1.00(ABZY.3)C0 or later, and verify that DNS access controls are properly enforced when the device is operating in AP mode.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Nbg7510 FirmwareOperating system
Affected:<= 1.00\(abzy.2\)c0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify device model and firmware version
    Access the router web interface (typically http://192.168.1.1) and navigate to Status or System Info page to view the device model (NBG7510) and firmware version. Alternatively, check via CLI using 'show version' or similar command if SSH/Telnet is enabled.
    Affected if The device is a Zyxel NBG7510 running firmware version 1.00(abzy.2)c0 or earlier (any version <= 1.00(abzy.2)c0).
  2. Verify the device operating mode
    In the router web interface, navigate to Network Setup or Operating Mode settings. Check whether the device is configured to operate in AP (Access Point) mode, also sometimes labeled as 'Bridge' or 'Wireless AP' mode.
    Affected if The device is configured to operate in AP mode (this is the required condition for the vulnerability to be exploitable).
  3. Test DNS service accessibility from external network
    From a device on a different network segment (not the LAN behind the router), attempt to send DNS queries to the router's IP address using tools like 'nslookup' or 'dig' directed at the router's LAN IP (e.g., nslookup example.com <router_LAN_IP>).
    Affected if DNS queries are successfully resolved when sent from an unauthorized network segment, indicating the DNS service is exposed without proper access controls.
  4. Inspect DNS proxy/relay configuration
    In the router web interface, go to LAN settings or DNS settings section. Look for DNS proxy, DNS relay, or DNS forwarding options. Check if there are any access control lists or IP restrictions configured for who can use the DNS service.
    Affected if No access restrictions are defined for the DNS service, or the DNS is configured to accept queries from any source (0.0.0.0/any), especially when in AP mode.

A user is affected if they have a Zyxel NBG7510 router running firmware <= 1.00(abzy.2)c0 and the device is configured to operate in AP mode with the DNS service accessible to unauthenticated network attackers.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 1.00
Interim mitigation

Update the device firmware to version V1.00(ABZY.3)C0 or later, and verify that DNS access controls are properly enforced when the device is operating in AP mode.

Recommended fix High confidence

V1.00(ABZY.3)C0

  1. Download firmware version V1.00(ABZY.3)C0 from the official Zyxel support website (www.zyxel.com)
  2. Access the NBG7510 device web management interface
  3. Navigate to the firmware upgrade section
  4. Upload and apply the V1.00(ABZY.3)C0 firmware file
  5. Verify the upgrade was successful by checking the firmware version in the device status

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Nbg7510 Firmware Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2022-38546 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
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  • Version or environment caveats, and links to real fixes
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