CVE-2021-3541 Denial of service in libxml2

Medium 6.5 Published 9 Jul 2021 Updated 14 Oct 2026

An attacker can cause a denial of service in applications using libxml2 by triggering an exponential entity expansion attack that bypasses existing protections.

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

What is CVE-2021-3541?

CVE-2021-3541 is a medium-severity denial of service vulnerability in Netapp Active Iq Unified Manager, published on 9 Jul 2021. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

A flaw was found in libxml2. Exponential entity expansion attack its possible bypassing all existing protection mechanisms and leading to denial of service.

Weakness: CWE-776

Which versions are affected by CVE-2021-3541?

It affects 19 products.

Linux distribution packages (16)

`libxml2` SUSE:Linux Enterprise Micro 5.0	All versions	`2.9.7-3.37.1`
`libxml2` SUSE:Linux Enterprise Module for Basesystem 15 SP2	All versions	`2.9.7-3.37.1`
`python-libxml2-python` SUSE:Linux Enterprise Module for Basesystem 15 SP2	All versions	`2.9.7-3.37.1`
`libxml2` SUSE:Linux Enterprise Module for Basesystem 15 SP3	All versions	`2.9.7-3.37.1`
`python-libxml2-python` SUSE:Linux Enterprise Module for Basesystem 15 SP3	All versions	`2.9.7-3.37.1`
`python-libxml2-python` SUSE:Linux Enterprise Module for Python 2 15 SP2	All versions	`2.9.7-3.37.1`
`python-libxml2-python` SUSE:Linux Enterprise Module for Python 2 15 SP3	All versions	`2.9.7-3.37.1`
`libxml2` SUSE:Linux Enterprise Server 12 SP5	All versions	`2.9.4-46.46.1`
`python-libxml2` SUSE:Linux Enterprise Server 12 SP5	All versions	`2.9.4-46.46.1`
`libxml2` SUSE:Linux Enterprise Server for SAP Applications 12 SP5	All versions	`2.9.4-46.46.1`
`python-libxml2` SUSE:Linux Enterprise Server for SAP Applications 12 SP5	All versions	`2.9.4-46.46.1`
`libxml2` SUSE:Linux Enterprise Software Development Kit 12 SP5	All versions	`2.9.4-46.46.1`
`libxml2` openSUSE:Leap 15.2	All versions	`2.9.7-lp152.10.15.1`
`python-libxml2-python` openSUSE:Leap 15.2	All versions	`2.9.7-lp152.10.15.1`
`libxml2` openSUSE:Leap 15.3	All versions	`2.9.7-3.37.1`
`python-libxml2-python` openSUSE:Leap 15.3	All versions	`2.9.7-3.37.1`

Products include Netapp Active Iq Unified Manager, Netapp Cloud Backup, Netapp Clustered Data Ontap, Netapp Clustered Data Ontap Antivirus Connector, Netapp H300e Firmware, Netapp H300s Firmware and 13 more.

How do I fix CVE-2021-3541?

Apply the vendor's patch.

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-2021-3541 being exploited?

There is no known exploitation of CVE-2021-3541 in the wild and no public exploit code.

All Netapp Active Iq Unified Manager vulnerabilities

Sources

Also known as ALPINE-CVE-2021-3541, DEBIAN-CVE-2021-3541, DLA-2669-1, ECHO-1bf6-54de-117e, GHSA-wcgr-63g6-pj93, JLSEC-2025-73 and 7 more.