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Authorization Bypass (IDOR)Weakness · CWE-639

CVE-2026-44776

MEDIUM · 5.9 CVSS v4.0 Published 2026-05-26
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
65/100
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
Kavita is a cross platform reading server. Prior to 0.9.0, the download, size-check, and chapter metadata endpoints do not enforce library-level authorization. A low-privileged user who knows or guesses a chapterId, volumeId, or seriesId belonging to a library they are not assigned to can download the full file contents, query file sizes, and read metadata for that content. This affects /api/Download/volume-size, /api/Download/chapter-size, /api/Download/series-size, /api/Download/volume, /api/Download/chapter, /api/Download/series, and /api/Chapter. This vulnerability is fixed in 0.9.0.

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

Kavita versions prior to 0.9.0 contain an Insecure Direct Object Reference (IDOR) vulnerability where download and metadata endpoints fail to enforce library-level authorization. Users assigned to one library can access files, file sizes, and metadata from other libraries by knowing or guessing the relevant IDs (chapterId, volumeId, seriesId).

MitigationUpgrade to Kavita version 0.9.0 or later, which implements proper library-level authorization checks on all affected endpoints.

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
High
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/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 Kavita installation and version
    Locate the Kavita installation directory or container, then check the version file or the application's /api/server/info endpoint to determine the running version.
    Affected if The installed version is prior to 0.9.0 (e.g., 0.8.x, 0.7.x, etc.)
  2. Confirm API endpoints are accessible
    Verify that the Kavita web API is exposed by checking the application's configuration or attempting to reach endpoints such as /api/Server/info, /api/Download/chapter, or /api/Chapter.
    Affected if The API endpoints are accessible over the network (localhost or remote).
  3. Check for multi-library user configuration
    Review user accounts in Kavita to determine if any users have access to only some libraries while being excluded from others, creating the condition where unauthorized access could occur.
    Affected if There exist users with restricted library access (not all users have admin or full library access).
  4. Verify authorization behavior on restricted endpoints
    Using a low-privileged test user account that has access to only certain libraries, attempt to access /api/Download/chapter, /api/Download/volume, or /api/Chapter endpoints with IDs from libraries the user is NOT assigned to.
    Affected if The API returns file content or metadata for libraries the test user is not assigned to (IDOR response rather than 403 Forbidden).

A user is affected if running a Kavita version prior to 0.9.0 with the API accessible and users having restricted library assignments, where the API incorrectly returns content from unauthorized libraries.

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 Kavita version 0.9.0 or later, which implements proper library-level authorization checks on all affected endpoints.

Recommended fix High confidence

0.9.0

  1. 1. Backup your existing Kavita installation and database before upgrading
  2. 2. Download Kavita version 0.9.0 or later from the official GitHub releases repository (github.com/Kareadita/Kavita)
  3. 3. Stop the Kavita service
  4. 4. Replace the existing Kavita binaries with version 0.9.0
  5. 5. Start the Kavita service
  6. 6. Verify that the library-level authorization is now enforced by testing that a low-privileged user cannot access content from unassigned libraries using the affected endpoints
Caveat Review release notes for 0.9.0 to check for any configuration or database migration requirements

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

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,440
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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-2026-44776 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
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