CVE-2021-32030
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 · uneditedThe administrator application on ASUS GT-AC2900 devices before 3.0.0.4.386.42643 and Lyra Mini before 3.0.0.4_384_46630 allows authentication bypass when processing remote input from an unauthenticated user, leading to unauthorized access to the administrator interface. This relates to handle_request in router/httpd/httpd.c and auth_check in web_hook.o. An attacker-supplied value of '\0' matches the device's default value of '\0' in some situations. Note: All versions of Lyra Mini and earlier which are unsupported (End-of-Life, EOL) are also affected by this vulnerability, Consumers can mitigate this vulnerability by disabling the remote access features from WAN.
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 · high confidenceAuthentication bypass vulnerability in ASUS GT-AC2900 and Lyra Mini routers allows unauthenticated remote attackers to access the administrator interface. The flaw exists in handle_request (httpd.c) and auth_check (web_hook.o) where an attacker-supplied null byte ('\0') matches the device's default null byte value, bypassing authentication checks.
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< 3.0.0.4.384.46630< 3.0.0.4.386.42643CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify your router modelLocate the device label on your ASUS router or access the admin interface to confirm the exact model number (GT-AC2900 or Lyra Mini)Affected if The device is an ASUS GT-AC2900 or Lyra Mini router
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Check the installed firmware versionLog into the router admin interface, navigate to Administration > Firmware Upgrade, or use the ASUS Router app to view the current firmware version. Compare the version number to the affected ranges: Lyra Mini < 3.0.0.4.384.46630 or GT-AC2900 < 3.0.0.4.386.42643Affected if The firmware version is lower than 3.0.0.4.384.46630 for Lyra Mini or lower than 3.0.0.4.386.42643 for GT-AC2900
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Verify if remote administration is enabledIn the router admin interface, go to WAN > Remote Access (or Administration > System > Remote Access), and check if the option to allow access from WAN is turned on or if port forwarding to the HTTP service is configuredAffected if Remote administration/WAN access is enabled, allowing the vulnerability to be exploited from outside the local network
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Inspect HTTP service configurationCheck the router's HTTP daemon settings (httpd) in Administration > System > Service or review any custom firewall rules that expose the web interface to external connectionsAffected if The HTTP service (port 80/443) is exposed to WAN or has open firewall rules permitting external access to the admin interface
Your environment is affected if you own a GT-AC2900 or Lyra Mini router running firmware below the safe version thresholds AND remote administration or WAN access to the router's web interface is enabled.
Generated from the published advisory. Verify against your own configuration.
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 · scoped3.0.0.4.384.466303.0.0.4.386.42643
Disable remote access features from WAN on affected ASUS devices to prevent unauthenticated access to the administrator interface from external networks.
GT-AC2900: Firmware 3.0.0.4.386.42643 or later | Lyra Mini: Firmware 3.0.0.4_384_46630 or later (if available - device may be EOL)
- 1. Identify your device model (GT-AC2900 or Lyra Mini) and check current firmware version in the router administration interface under 'Administration' > 'Firmware Upgrade'
- 2. For GT-AC2900: Navigate to the ASUS support website (www.asus.com), search for GT-AC2900, and download firmware version 3.0.0.4.386.42643 or later
- 3. For Lyra Mini: Navigate to the ASUS support website (www.asus.com), search for Lyra Mini, and download firmware version 3.0.0.4_384_46630 or later. Note: Lyra Mini may be EOL; if no firmware is available, proceed to mitigation step
- 4. Access the router's admin interface, go to Administration > Firmware Upgrade, and upload the downloaded firmware file
- 5. Wait for the firmware to flash and the router to reboot (typically 2-5 minutes)
- 6. Verify the new firmware version is installed correctly
- 7. As an alternative mitigation (especially for EOL devices): Go to WAN > Remote Access (or similar), and disable 'Enable Web Access from WAN' or 'Remote Management' to prevent external access
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation16.0 h
- Testing8.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2021-32030 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-32030 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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