# CVE-2021-3541: Denial of service in libxml2 > An attacker can cause a denial of service in applications using libxml2 by triggering an exponential entity expansion attack that bypasses existing protections. - **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 9 Jul 2021 - **Updated:** 14 Oct 2026 - **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, MGASA-2021-0232, OESA-2021-1222, SUSE-SU-2021:1917-1, SUSE-SU-2021:2016-1, UBUNTU-CVE-2021-3541, openSUSE-SU-2021:0886-1, openSUSE-SU-2021:1917-1 ## 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 (Improper Restriction of Recursive Entity References in DTDs) ## Which versions are affected by CVE-2021-3541? It affects 19 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `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: Netapp Active Iq Unified Manager, Netapp Cloud Backup, Netapp Clustered Data Ontap, Netapp Clustered Data Ontap Antivirus Connector, Netapp H300e Firmware, Netapp H300s Firmware, Netapp H410c Firmware, Netapp H410s Firmware, Netapp H500e Firmware, Netapp H500s Firmware, Netapp H700e Firmware, Netapp H700s Firmware, Netapp Manageability Software Development Kit, Netapp Ontap Select Deploy Administration Utility, Netapp Smi-S Provider, Netapp Snapdrive, Oracle Zfs Storage Appliance Kit, Redhat Jboss Core Services, Xmlsoft Libxml2. ## How do I fix CVE-2021-3541? Apply the vendor's patch. ## Is CVE-2021-3541 being exploited? There is no known exploitation of CVE-2021-3541 in the wild and no public exploit code. ## Other vulnerabilities in Netapp Active Iq Unified Manager - [CVE-2022-31692](https://insights.sbomify.com/CVE-2022-31692/): Spring Security authorization rules can be bypassed via forward or include dispatcher types (critical 9.8) - [CVE-2022-2526](https://insights.sbomify.com/CVE-2022-2526/): Use after free in systemd-resolved (critical 9.8) - [CVE-2022-22978](https://insights.sbomify.com/CVE-2022-22978/): Authorization bypass in Spring Security (critical 9.8) - [CVE-2021-22931](https://insights.sbomify.com/CVE-2021-22931/): Code injection in Node (critical 9.8) - [CVE-2018-2938](https://insights.sbomify.com/CVE-2018-2938/): Code injection in Java (critical 9.0) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2021-3541 and fix it if it is affected. What it is: 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. Exploitation: There is no known exploitation of CVE-2021-3541 in the wild and no public exploit code. Affected product: Netapp Active Iq Unified Manager. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2021-3541/ (Markdown: https://insights.sbomify.com/CVE-2021-3541/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3541 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3541 - OSV: https://osv.dev/vulnerability/CVE-2021-3541 --- From sbomify Insights: https://insights.sbomify.com/CVE-2021-3541/ Summaries are generated and may contain mistakes; the official description above is the record.