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Improper AuthorizationWeakness · CWE-285

CVE-2026-23623

MEDIUM · 5.3 CVSS v3.1 Published 2026-02-06
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
62/100
Remediation priority · Elevated
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
Collabora Online is a collaborative online office suite based on LibreOffice technology. Prior to Collabora Online Development Edition version 25.04.08.2 and prior to Collabora Online versions 23.05.20.1, 24.04.17.3, and 25.04.7.5, a user with view-only rights and no download privileges can obtain a local copy of a shared file. Although there are no corresponding buttons in the interface, pressing Ctrl+Shift+S initiates the file download process. This allows the user to bypass the access restrictions and leads to unauthorized data retrieval. This issue has been patched in Collabora Online Development Edition version 25.04.08.2 and Collabora Online versions 23.05.20.1, 24.04.17.3, and 25.04.7.5.

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

Collabora Online fails to enforce view-only access controls on the Ctrl+Shift+S keyboard shortcut, allowing users without download privileges to bypass UI restrictions and retrieve local copies of shared files. The download functionality exists but is hidden from the interface, yet remains accessible via this undocumented keyboard combination.

MitigationUpgrade to Collabora Online Development Edition version 25.04.08.2 or the patched versions 23.05.20.1, 24.04.17.3, or 25.04.7.5 to remediate this access control bypass.

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
Low
Integrity
None
Availability
None

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

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 Collabora Online installation and version
    Check the installed package version using the package manager (e.g., `dpkg -l | grep collabora`, `rpm -q collabora`, or check the Docker image tag if running containerized)
    Affected if The installed version is earlier than 23.05.20.1, or falls between 23.05.20.1 and 24.04.17.3, or between 24.04.17.3 and 25.04.7.5, or between 25.04.7.5 and 25.04.08.2
  2. Verify view-only access control configuration
    Inspect the WOPI host configuration (typically in loolwsd.xml or the WOPI injector configuration) to confirm that download permissions are disabled for certain users or groups using the 'disable_download' or similar setting
    Affected if Download permissions are explicitly disabled in the configuration but the interface restriction is the only enforcement mechanism
  3. Test Ctrl+Shift+S shortcut bypass
    In a Collabora Online session with a user account that has view-only permissions (no download capability visible in UI), press Ctrl+Shift+S and observe whether a download or save dialog appears
    Affected if The shortcut triggers a download/save dialog despite view-only restrictions being applied in the UI
  4. Check for unfiltered WOPI endpoint access
    Examine server logs or network traffic for requests to the download endpoint (typically /lool/convert-to/ or /lool/download) originating from users with view-only permissions
    Affected if Download requests are being processed for users who should only have view-only access based on WOPI permission settings

A user is affected if their Collabora Online version is below 25.04.08.2 (or the interim patched versions) AND view-only restrictions are configured in the WOPI host, as the Ctrl+Shift+S shortcut can bypass the UI hiding of the download functionality.

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 Collabora Online Development Edition version 25.04.08.2 or the patched versions 23.05.20.1, 24.04.17.3, or 25.04.7.5 to remediate this access control bypass.

Recommended fix High confidence

Collabora Online Development Edition 25.04.08.2 (or any of: 23.05.20.1, 24.04.17.3, 25.04.7.5 for standard editions)

  1. Identify the currently installed Collabora Online version using your package manager or admin interface
  2. Upgrade to Collabora Online Development Edition version 25.04.08.2 or later, OR upgrade to one of the standard versions: 23.05.20.1, 24.04.17.3, or 25.04.7.5
  3. Verify the upgrade completed successfully by checking the version number in the admin interface
  4. Test that view-only users can no longer download files using Ctrl+Shift+S or any other method

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
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
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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-2026-23623 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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