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Incorrect Privilege AssignmentWeakness · CWE-266

CVE-2026-7709

MEDIUM · 6.3 CVSS v3.1 Published 2026-05-03
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
69/100
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
A vulnerability was identified in janeczku Calibre-Web up to 0.6.26. The impacted element is the function generate_auth_token of the file cps/kobo_auth.py of the component Endpoint. Such manipulation of the argument user_id leads to improper authorization. The attack may be launched remotely. The exploit is publicly available and might be used. The vendor was contacted early about this disclosure but did not respond in any way.

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 · moderate confidence

Calibre-Web's Kobo integration has an improper authorization vulnerability in the generate_auth_token function in cps/kobo_auth.py. By manipulating the user_id parameter, an attacker can potentially generate authentication tokens for arbitrary users, bypassing proper authorization checks. This allows unauthorized access to user accounts through the affected endpoint.

MitigationSince the vendor did not respond and no official patch is available, implement proper authorization validation in generate_auth_token to verify the requesting user has permission to generate tokens for the target user_id. If a newer version exists, upgrade immediately.

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
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/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. Confirm Calibre-Web installation and version
    Locate the Calibre-Web installation directory and check the version.py file or git tags. Common locations: /opt/calibre-web, /app, or the directory where the application was installed.
    Affected if The installed version is within any unpatched range and the specific version cannot be confirmed as fixed.
  2. Verify cps/kobo_auth.py exists
    Check for the presence of cps/kobo_auth.py in the Calibre-Web installation directory. This file contains the vulnerable generate_auth_token function.
    Affected if The file exists, indicating the Kobo integration code is present in the environment.
  3. Check if Kobo sync is enabled
    Examine the Calibre-Web configuration (app.db or config.db) to determine whether the Kobo sync feature is enabled. Look for kobo-related settings or sync configuration flags.
    Affected if Kobo sync is enabled, making the vulnerable endpoint potentially accessible.
  4. Inspect generate_auth_token function
    Review the source code of cps/kobo_auth.py and locate the generate_auth_token function. Verify whether proper authorization validation exists that checks if the requesting user has permission to generate tokens for the target user_id.
    Affected if The function lacks or has inadequate authorization checks on the user_id parameter.
  5. Check endpoint accessibility
    If possible, examine the web server routing or application endpoints to confirm the Kobo auth endpoint is exposed. Look for routes pointing to /kobo or similar paths.
    Affected if The Kobo authentication endpoint is exposed without proper access controls.

A user is affected if running Calibre-Web with the cps/kobo_auth.py file present, with Kobo integration enabled, and the generate_auth_token function lacks proper authorization validation on the user_id parameter.

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

Since the vendor did not respond and no official patch is available, implement proper authorization validation in generate_auth_token to verify the requesting user has permission to generate tokens for the target user_id. If a newer version exists, upgrade immediately.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA3.0 h
16.0 hours of engineering $2,820
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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-2026-7709 in production — separate from our analysis above.

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