What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-10-25 · updated 2026-06-17
• Weakness: CWE-200

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.

Affected products

• nextcloud Officeonline: before 1.1.1 — fixed in 1.1.1

How to fix

Upgrade to a fixed version: nextcloud Officeonline 1.1.1. Check the vendor advisory for mitigations.

References

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

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