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Hard-coded CredentialsWeakness · CWE-798

CVE-2026-36606

HIGH · 7.1 CVSS v3.1 Published 2026-06-03
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
73/100
Remediation priority · Elevated
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
Mercusys AC12G (EU) V1 router with firmware AC12G(EU)_V1_200909 encrypts configuration backups with a hardcoded DES key using single DES in ECB mode. An attacker who obtains a backup file can decrypt it to recover all stored credentials including admin password, WiFi PSK, and DDNS credentials.

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 Mercusys AC12G router firmware uses a hardcoded DES key in ECB mode to encrypt configuration backups. Since Single DES with a known key is trivially breakable and ECB mode leaks patterns, an attacker with a captured backup file can decrypt it to recover sensitive credentials including the admin password, WiFi PSK, and DDNS credentials.

MitigationUntil a firmware update is released, restrict physical and network access to the router's backup files. Administrators should change credentials after any firmware update and consider using a strong unique admin password and WiFi passphrase.

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

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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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. Confirm device model
    Log into the router web admin interface (typically 192.168.0.1) and check the Status or Device Info page for the exact model number. Alternatively, check the product label on the device itself.
    Affected if Device is NOT a Mercusys AC12G router (other models are not affected by this specific CVE)
  2. Identify firmware version
    In the router admin interface, navigate to the Firmware Upgrade or System Settings page to view the current firmware version. Record this version for comparison.
    Affected if Firmware version is older than the patched version that addresses the hardcoded DES key (if a patch has been released)
  3. Locate backup export feature
    In the router admin interface, look for a System Tools, Maintenance, or Backup/Restore section. Determine if a configuration backup export option exists.
    Affected if The router lacks a configuration backup feature (the vulnerability only applies when this feature exists)
  4. Verify backup file accessibility
    Attempt to export a configuration backup file if the feature is available. Note whether the file downloads successfully and its file extension (commonly .bin or .cfg).
    Affected if Backup files can be downloaded without authentication or through an unauthorized path (the vulnerability requires access to a backup file)
  5. Examine backup file encryption
    Open the downloaded backup file in a hex editor or use 'file' command. DES-encrypted files will appear as random bytes without plaintext headers. The hardcoded key vulnerability means any backup can be decrypted with the known key.
    Affected if Backup file contains encrypted data with no visible plaintext credentials (indicating encryption is in use, which is required for this vulnerability to apply)

Your environment is affected if you are using a Mercusys AC12G router with a firmware version prior to the patched release, and the configuration backup feature is accessible and produces encrypted backup files.

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

Until a firmware update is released, restrict physical and network access to the router's backup files. Administrators should change credentials after any firmware update and consider using a strong unique admin password and WiFi passphrase.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
17.0 hours of engineering $3,000
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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-2026-36606 in production — separate from our analysis above.

No notes yet

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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
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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