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4g03 Pro FirmwareOperating system · Tenda

CVE-2026-5527

MEDIUM · 5.3 CVSS v3.1 Published 2026-04-05
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
62/100
Remediation priority · Elevated
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 weakness has been identified in Tenda 4G03 Pro 1.0/1.0re/01.bin/04.03.01.53. Affected by this issue is some unknown functionality of the file /etc/www/pem/server.key of the component ECDSA P-256 Private Key Handler. This manipulation causes use of hard-coded cryptographic key . It is possible to initiate the attack remotely.

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 confidence

The Tenda 4G03 Pro router firmware contains a hard-coded ECDSA P-256 private key stored in /etc/www/pem/server.key. This hard-coded key is identical across all affected devices, allowing an attacker who obtains or derives the key to decrypt encrypted communications, impersonate the device, or perform man-in-the-middle attacks. The issue is remotely exploitable.

MitigationReplace the hard-coded private key with a unique, randomly generated key per device, and implement proper certificate management that allows certificate rotation. Users should regenerate or replace certificates on affected devices.

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
4g03 Pro FirmwareOperating system
Affected:= 04.03.01.53

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
Low
Integrity
None
Availability
None

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

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
    Check if the device is a Tenda 4G03 Pro router. This may be visible on the device label, in the web interface, or via commands like 'cat /proc/cpuinfo' or 'nvram get device_name'
    Affected if The device is not a Tenda 4G03 Pro (not affected)
  2. Check firmware version
    Determine the installed firmware version. This may be accessible via the web admin interface under System/Firmware info, or via command line such as 'cat /proc/version' or 'nvram get firmware_version'
    Affected if Firmware version is exactly 04.03.01.53 (affected). If version differs, compare to the affected range.
  3. Locate the private key file
    Check if the file /etc/www/pem/server.key exists on the device. Use 'ls -la /etc/www/pem/server.key' or 'cat /etc/www/pem/server.key' if accessible via SSH/Telnet
    Affected if File /etc/www/pem/server.key does not exist (not affected)
  4. Verify key type is ECDSA P-256
    Examine the key file content using 'openssl ec -in /etc/www/pem/server.key -text -noout' or similar to confirm it is an ECDSA P-256 private key
    Affected if The file exists but is not an ECDSA P-256 key (not affected)
  5. Confirm hard-coded key presence
    If the ECDSA P-256 private key exists at /etc/www/pem/server.key, this indicates the hard-coded key vulnerability. Compare the key against a known extracted key or check if multiple devices of the same model share identical keys
    Affected if An ECDSA P-256 private key is present at /etc/www/pem/server.key in firmware 04.03.01.53 (affected)

A defender is affected if they have a Tenda 4G03 Pro device running firmware version 04.03.01.53 that contains an ECDSA P-256 private key at /etc/www/pem/server.key.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Replace the hard-coded private key with a unique, randomly generated key per device, and implement proper certificate management that allows certificate rotation. Users should regenerate or replace certificates on affected devices.

Fix this in 4g03 Pro Firmware Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,980
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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-2026-5527 in production — separate from our analysis above.

No notes yet

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What this is

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