Read the docs
TI-2026-83142 Aliases CVE-2026-46499

Collabora Online read-only bypass lets viewers change live documents

Priority LOW 20CWE-863Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
None · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-863.

Summary

Collabora Online before 24.04.18 and from 25.04.0-0 before 25.04.11 has an incorrect authorization flaw (CWE-863). Several document operations delegated to LibreOfficeKit do not enforce a session's read-only state. A read-only user, such as a viewer-role WOPI user, can send crafted WebSocket messages to run document-changing UNO commands. The changes can mislead co-viewers, or an editor sharing the session can unknowingly save them.

Written with Claude Haiku 5.5 from the sources below · 2026-10-30

Description from the CNA

Collabora Online is a collaborative online office suite based on LibreOffice technology. Prior to 24.04.18 and 25.04.11, several document operations delegated to `LibreOfficeKit` in the per-document kit process fail to enforce a session's read-only state. A read-only user, such as a viewer-role WOPI user, can send crafted `WebSocket` messages to execute document-mutating `UNO` commands and dialog operations despite the read-only interface. The changes can mislead co-viewers within the live session, or an authorized editor sharing the session can unknowingly save the modifications. The read-only attacker cannot save the document directly, and changes are discarded when the kit session ends unless an authorized editor saves them. This issue is fixed in versions 24.04.18 and 25.04.11.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00249 16th percentileScored 2026-11-07
Fix Fixed online (CollaboraOnline): 24.04.18, 25.04.11

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Collaboraonlinebefore 24.04.18; 25.04.0-0 to before 25.04.1124.04.18, 25.04.11Patch availableCNA
  • online VendorCollabora Affected before 24.04.18; 25.04.0-0 to before 25.04.11 Fixed in 24.04.18, 25.04.11 Patch available CNA

Remediation

Upgrade Collabora Online to version 24.04.18 or 25.04.11, which fix this flaw.

Written with Claude Haiku 5.5 from the sources below · 2026-10-30

  • Fix · CNA online (CollaboraOnline) Fixed in 24.04.18, 25.04.11

Timeline

  1. 2026-10-30 Threatist record created from CVE-2026-46499
  2. 2026-11-05 CISA SSVC decision points changed

References

Other 1

  • TI-2026-73868 Collabora Online Built-in CODE Server allows remote code execution KEVCVSS 4.0CRITICAL 9.2
  • TI-2026-19024 Collabora Online vulnerable to Authorization Bypass CVSS 3.1MEDIUM 5.3
  • TI-2021-12412 Unauthenticated attacker could gain access to currently open files CVSS 3.1CRITICAL 9.8
  • TI-2025-40711 Configuration-Dependent RCE (OS Command Injection) in richdocumentscode proxy CVSS 4.0HIGH 7.2
  • TI-2023-16934 Collabora Online has Stored Cross-Site-Scripting vulnerability in admin interface CVSS 3.1HIGH 8.7
  • TI-2025-20570 Collabora Online Vulnerable to Arbitrary File Write CVSS 4.0HIGH 8.3
See all 19 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences