Bug 1964016 (CVE-2021-28905)

Summary:	CVE-2021-28905 libyang: reachable assertion in lys_node_free()
Product:	[Other] Security Response	Reporter:	Guilherme de Almeida Suckevicz <gsuckevi>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	mruprich, tkorbar
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	libyang 1.0.225	Doc Type:	If docs needed, set a value
Doc Text:	A flaw was found in libyang. An assertion in lys_node_free function may be reached or, if assertions are disabled, a NULL pointer dereference could be triggered allowing a remote attacker to crash an application that uses libyang with user-controlled YIN data. The highest threat from this vulnerability is the service availability.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-10-28 12:28:46 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:	1964017, 1965258, 1965259
Bug Blocks:	1964021

Description Guilherme de Almeida Suckevicz 2021-05-24 14:43:54 UTC

In function lys_node_free() in libyang <= v1.0.225, it asserts that the value of node->module can't be NULL. But in some cases, node->module can be null, which triggers a reachable assertion (CWE-617).

Reference:
https://github.com/CESNET/libyang/issues/1452

Comment 1 Guilherme de Almeida Suckevicz 2021-05-24 14:44:12 UTC

Created libyang tracking bugs for this issue:

Affects: fedora-all [bug 1964017]

Comment 2 Riccardo Schirone 2021-05-27 09:39:47 UTC

Upstream patch:
https://github.com/CESNET/libyang/commit/5ce30801f9ccc372bbe9b7c98bb5324b15fb010a