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Authorization Bypass (IDOR)Weakness · CWE-639

CVE-2026-29200

CRITICAL · 9.9 CVSS v4.0 Published 2026-05-04
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

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 critical IDOR vulnerability has been discovered in Comet Backup affecting all versions from 20.11.0 to 26.1.1 and 26.2.1. The vulnerability allows a tenant administrator to impersonate any end-user account of other tenants on the same server via a vulnerable API call.

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

An IDOR vulnerability in Comet Backup's API allows a tenant administrator to manipulate object references in API calls to impersonate end-user accounts belonging to other tenants on the same server, achieving horizontal privilege escalation across tenant boundaries.

MitigationUpgrade Comet Backup to a patched version beyond 26.2.1. Until patched, restrict API access to trusted personnel only and implement logging/monitoring for suspicious cross-tenant account access patterns.

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
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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 Comet Backup installation and version
    Locate Comet Backup installation directory or check system services. Run 'cometbackup --version' or check installed package version via system package manager.
    Affected if Comet Backup version is 26.2.1 or earlier and the API feature is enabled.
  2. Verify API functionality is enabled
    Check Comet Backup configuration files (typically in /etc/cometbackup/ or installation directory) for API settings. Look for 'enable_api' or similar configuration flags.
    Affected if API access is enabled in the Comet Backup configuration.
  3. Confirm multi-tenant setup exists
    Check if multiple tenant organizations are configured in Comet Backup. Query the Comet Backup server database or use admin interface to list tenant organizations.
    Affected if More than one tenant organization exists on the same Comet Backup server.
  4. Review API access controls and authentication
    Examine API authentication settings and tenant isolation policies in Comet Backup configuration files. Check for role-based access control (RBAC) settings for API users.
    Affected if API users with tenant administrator roles can manipulate object references without proper cross-tenant validation.
  5. Inspect API request logging for cross-tenant access patterns
    Review Comet Backup API access logs for requests where tenant_admin_user_id or similar object references differ from the authenticated tenant.
    Affected if Logs show API calls accessing resources from other tenant IDs than the authenticated user's tenant.

A user is affected if running Comet Backup version 26.2.1 or earlier with the API enabled in a multi-tenant environment, where API requests can reference objects across tenant boundaries without proper isolation validation.

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

Upgrade Comet Backup to a patched version beyond 26.2.1. Until patched, restrict API access to trusted personnel only and implement logging/monitoring for suspicious cross-tenant account access patterns.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing8.0 h
  • Review / QA4.0 h
24.0 hours of engineering $4,160
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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-2026-29200 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
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