Bug 1981502 (CVE-2021-32688)

Summary:	CVE-2021-32688 nextcloud: Improper permission check permits tokens to change their own permissions
Product:	[Other] Security Response	Reporter:	Pedro Sampaio <psampaio>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED UPSTREAM	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	ce, james.hogarth
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-07-12 22:40:21 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1981503
Bug Blocks:

Description Pedro Sampaio 2021-07-12 17:26:44 UTC

Nextcloud Server is a Nextcloud package that handles data storage. Nextcloud Server supports application specific tokens for authentication purposes. These tokens are supposed to be granted to a specific applications (e.g. DAV sync clients), and can also be configured by the user to not have any filesystem access. Due to a lacking permission check, the tokens were able to change their own permissions in versions prior to 19.0.13, 20.0.11, and 21.0.3. Thus fileystem limited tokens were able to grant themselves access to the filesystem. The issue is patched in versions 19.0.13, 20.0.11, and 21.0.3. There are no known workarounds aside from upgrading.

https://hackerone.com/reports/1193321
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-48m7-7r2r-838r
https://github.com/nextcloud/server/pull/27000

Comment 1 Pedro Sampaio 2021-07-12 17:27:05 UTC

Created nextcloud tracking bugs for this issue:

Affects: fedora-all [bug 1981503]

Comment 2 Product Security DevOps Team 2021-07-12 22:40:21 UTC

This CVE Bugzilla entry is for community support informational purposes only as it does not affect a package in a commercially supported Red Hat product. Refer to the dependent bugs for status of those individual community products.