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Incorrect AuthorizationWeakness · CWE-863

CVE-2026-53521

MEDIUM · 6.4 CVSS v3.1 Published 2026-06-12
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
70/100
Remediation priority · Elevated
Remotely reachable 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
Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From version 2.0.14 to before version 2.1.0, PATCH /server/{id} accepts and persists nonexistent ddns_profiles IDs for a member-owned server. If another user later creates a DDNS profile with one of those IDs, the DDNS worker resolves the stored ID and dispatches an update using the other user's DDNS profile configuration in the context of the attacker's server. This issue has been patched in version 2.1.0.

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

Nezha Monitoring versions 2.0.14 through before 2.1.0 contain an Insecure Direct Object Reference (IDOR) vulnerability via PATCH /server/{id}. The endpoint accepts and persists nonexistent ddns_profiles IDs for member-owned servers. When another user later creates a DDNS profile using one of those orphaned IDs, the system's DDNS worker resolves that ID and dispatches updates using the other user's DDNS profile configuration in the context of the attacker's server, enabling cross-user profile hijacking.

MitigationUpgrade to Nezha Monitoring version 2.1.0 or later. Until then, consider restricting DDNS profile creation or adding application-level validation to ensure stored ddns_profiles IDs belong to the requesting user.

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
Low
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
Low
Availability
Low

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

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 Nezha Monitoring installation and version
    Check the Nezha Monitoring version by querying the application API, checking the dashboard About page, or inspecting the binary/container version (e.g., docker images, binary --version, or the /api/v1/server/version endpoint if available).
    Affected if The installed version is 2.0.14 or any version from 2.0.15 through 2.0.x up to but not including 2.1.0.
  2. Confirm DDNS feature is enabled
    Navigate to the Nezha dashboard and check if any DDNS profiles have been created under the server configuration. Alternatively, query the server API endpoint for ddns_profiles configuration.
    Affected if DDNS profiles exist and are assigned to servers in the environment.
  3. Inspect server configurations for orphaned ddns_profiles IDs
    Use the Nezha API (GET /api/v1/servers) or database query to retrieve all server records and examine the ddns_profile_id fields. Look for IDs that do not exist in the ddns_profiles table or that belong to other users.
    Affected if Any server record contains a ddns_profile_id that references a profile owned by a different user, or references a profile ID that does not exist in the ddns_profiles table.
  4. Review audit logs for DDNS profile assignment changes
    Check application logs for PATCH /server/{id} requests that modified ddns_profile_id fields, particularly those assigning IDs that were not pre-existing in the ddns_profiles table.
    Affected if Logs show PATCH requests assigning non-existent or cross-user ddns_profile_id values to member-owned servers.

You are affected if Nezha Monitoring version 2.0.14 through before 2.1.0 is running, DDNS profiles are in use, and server configurations contain orphaned or cross-user ddns_profile_id references.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to Nezha Monitoring version 2.1.0 or later. Until then, consider restricting DDNS profile creation or adding application-level validation to ensure stored ddns_profiles IDs belong to the requesting user.

Recommended fix Moderate confidence

2.1.0

  1. 1. Backup your current Nezha Monitoring installation and database
  2. 2. Check your current Nezha Monitoring version (likely via admin panel or `nezha --version` CLI command)
  3. 3. Download version 2.1.0 from the official GitHub repository (github.com/nezhahq/nezha)
  4. 4. Follow the official upgrade instructions for your deployment method (Docker, binary, or source)
  5. 5. Verify the upgrade was successful by checking the version number
  6. 6. Test that PATCH /server/{id} now properly validates ddns_profiles IDs before persistence
Caveat Review release notes for any breaking changes between your current version and 2.1.0; security patches typically have minimal breaking changes

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

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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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-2026-53521 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
  • 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