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VulnerabilityAwaiting classification

CVE-2026-11405

CRITICAL · 9.8 CVSS v3.1 Published 2026-07-06
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click 7 weeks old

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
The web server binary /bin/httpd contains a hidden backdoor authentication mechanism in the login() function at 004c88b8. - The function contains a normal authentication path using MD5/hash-based password verification (prod_encode64/PasswordToMd5/check_rand_key). - After normal authentication fails, it calls GetValue("sys.rzadmin.password") to read a backdoor password from the device configuration. - It performs a direct strcmp() comparison (plaintext, not hashed) between the config value and the user-supplied password. A successful match grants role=2 (admin-level access) and creates a valid session. The rzadmin username is never checked — any username works with the backdoor

In the news

Third-party coverage
Trending covered by 4 outlets this week · latest 1mo ago

Surfaced from public web coverage — external links open in a new tab.

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 /bin/httpd binary contains a hidden backdoor in the login() function that bypasses normal MD5-based authentication by checking a secondary password from device configuration (sys.rzadmin.password). It performs a plaintext strcmp() comparison against user input and grants admin-level access (role=2) on match, with no username validation required for the backdoor path.

MitigationApply vendor firmware/security patch to remove the backdoor code; verify the sys.rzadmin.password configuration value is not set or is changed to a strong unique value if the device is already deployed; restrict network access to the httpd service until patched.

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
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 the httpd binary version
    Locate the /bin/httpd binary and retrieve its version information using 'ls -la /bin/httpd' and any version flags such as 'httpd -v' or by checking firmware version with 'cat /proc/version' or 'uname -a'
    Affected if The binary version cannot be determined or falls within an unpatched firmware version range containing the backdoor code
  2. Check for the backdoor configuration password
    Examine the device configuration for the presence of 'sys.rzadmin.password' using 'grep -r "rzadmin" /config' or the device's configuration database, or check via the management interface if accessible
    Affected if The configuration parameter sys.rzadmin.password is defined and set to any value in the device configuration
  3. Verify the httpd service is exposed
    Check if the httpd service is listening on network ports using 'netstat -tlnp | grep httpd' or 'ss -tlnp | grep httpd', and identify accessible IP addresses
    Affected if The httpd service is running and bound to a network interface accessible from untrusted networks
  4. Inspect login behavior for the backdoor path
    If safe to do so without legal authorization for your specific environment, attempt a login with an empty or arbitrary username while using the configured sys.rzadmin.password value, observing if admin-level access (role=2) is granted without valid MD5 authentication
    Affected if Login succeeds with admin privileges using only the sys.rzadmin.password value regardless of username validity

The environment is affected if the device runs a firmware version containing the backdoor and has sys.rzadmin.password configured in the system configuration, with the httpd service accessible over the network.

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

Apply vendor firmware/security patch to remove the backdoor code; verify the sys.rzadmin.password configuration value is not set or is changed to a strong unique value if the device is already deployed; restrict network access to the httpd service until patched.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation8.0 h
  • Testing3.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,850
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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-2026-11405 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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data