CVE-2021-28905 Denial of service in n/a

High 7.5 Published 20 May 2021 Updated 3 Aug 2024

A reachable assertion failure in libyang allows attackers to cause a denial of service by triggering a null pointer condition in node freeing.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2021-28905?

CVE-2021-28905 is a high-severity denial of service vulnerability in n/a, published on 20 May 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

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).

Weakness: CWE-617

Which versions are affected by CVE-2021-28905?

It affects 1 product.

Linux distribution packages (4)

`libyang` SUSE:Linux Enterprise Module for Server Applications 15 SP3	All versions	`1.0.184-150300.3.3.1`
`libyang` SUSE:Linux Enterprise Module for Server Applications 15 SP4	All versions	`1.0.184-150300.3.3.1`
`libyang` openSUSE:Leap 15.3	All versions	`1.0.184-150300.3.3.1`
`libyang` openSUSE:Leap 15.4	All versions	`1.0.184-150300.3.3.1`

Products include Cesnet Libyang.

How do I fix CVE-2021-28905?

Upgrade to a fixed version.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2021-28905 being exploited?

There is no known exploitation of CVE-2021-28905 in the wild and no public exploit code.

Sources

Also known as DEBIAN-CVE-2021-28905, GHSA-qj7j-m28f-g68x, SUSE-SU-2022:2922-1, UBUNTU-CVE-2021-28905.