CVE Vulnerabilities

CVE-2021-28905

Reachable Assertion

Published: May 20, 2021 | Modified: Apr 05, 2022
CVSS 3.x
7.5
HIGH
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.x
5 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P
RedHat/V2
RedHat/V3
7.5 MODERATE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Ubuntu
LOW

In function lys_node_free() in libyang <= v1.0.225, it asserts that the value of node->module cant be NULL. But in some cases, node->module can be null, which triggers a reachable assertion (CWE-617).

Weakness

The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.

Affected Software

Name Vendor Start Version End Version
Libyang Cesnet * 1.0.225 (including)
Libyang Ubuntu esm-apps/focal *
Libyang Ubuntu focal *
Libyang Ubuntu groovy *
Libyang Ubuntu hirsute *
Libyang Ubuntu trusty *
Libyang Ubuntu upstream *
Libyang Ubuntu xenial *

Extended Description

While assertion is good for catching logic errors and reducing the chances of reaching more serious vulnerability conditions, it can still lead to a denial of service. For example, if a server handles multiple simultaneous connections, and an assert() occurs in one single connection that causes all other connections to be dropped, this is a reachable assertion that leads to a denial of service.

Potential Mitigations

References