# CVE-2021-3580: Denial of service in nettle > An attacker can cause a denial of service by providing specially crafted ciphertext to Nettle's RSA decryption functions, leading to application crashes. - **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 5 Aug 2021 - **Updated:** 14 Oct 2026 - **Also known as:** ALPINE-CVE-2021-3580, AZL-6741, CLSA-2026-1777451834, CLSA-2026-1777452099, CLSA-2026-1790604865, DEBIAN-CVE-2021-3580, GHSA-52fp-4722-wcjw, JLSEC-2026-576, OESA-2021-1320, SUSE-SU-2021:2135-1, SUSE-SU-2021:2143-1, UBUNTU-CVE-2021-3580, openSUSE-SU-2021:0906-1, openSUSE-SU-2021:2143-1 ## What is CVE-2021-3580? CVE-2021-3580 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 5 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description A flaw was found in the way nettle's RSA decryption functions handled specially crafted ciphertext. An attacker could use this flaw to provide a manipulated ciphertext leading to application crash and denial of service. Weakness: CWE-20 (Improper Input Validation) ## Which versions are affected by CVE-2021-3580? It affects 4 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `libnettle` | SUSE:Enterprise Storage 6 | All versions | 3.4.1-4.18.1 | | `libnettle` | SUSE:HPE Helion OpenStack 8 | All versions | 2.7.1-13.6.1 | | `libnettle` | SUSE:Linux Enterprise High Performance Computing 15 SP1-ESPOS | All versions | 3.4.1-4.18.1 | | `libnettle` | SUSE:Linux Enterprise High Performance Computing 15 SP1-LTSS | All versions | 3.4.1-4.18.1 | | `libnettle` | SUSE:Linux Enterprise High Performance Computing 15-ESPOS | All versions | 3.4.1-4.18.1 | | `libnettle` | SUSE:Linux Enterprise High Performance Computing 15-LTSS | All versions | 3.4.1-4.18.1 | | `libnettle` | SUSE:Linux Enterprise Micro 5.0 | All versions | 3.4.1-4.18.1 | | `libnettle` | SUSE:Linux Enterprise Module for Basesystem 15 SP2 | All versions | 3.4.1-4.18.1 | | `libnettle` | SUSE:Linux Enterprise Module for Basesystem 15 SP3 | All versions | 3.4.1-4.18.1 | | `libnettle` | SUSE:Linux Enterprise Server 12 SP2-BCL | All versions | 2.7.1-13.6.1 | | `libnettle` | SUSE:Linux Enterprise Server 12 SP3-BCL | All versions | 2.7.1-13.6.1 | | `libnettle` | SUSE:Linux Enterprise Server 12 SP3-LTSS | All versions | 2.7.1-13.6.1 | | `libnettle` | SUSE:Linux Enterprise Server 12 SP4-LTSS | All versions | 2.7.1-13.6.1 | | `libnettle` | SUSE:Linux Enterprise Server 12 SP5 | All versions | 2.7.1-13.6.1 | | `libnettle` | SUSE:Linux Enterprise Server 15 SP1-BCL | All versions | 3.4.1-4.18.1 | | `libnettle` | SUSE:Linux Enterprise Server 15 SP1-LTSS | All versions | 3.4.1-4.18.1 | | `libnettle` | SUSE:Linux Enterprise Server 15-LTSS | All versions | 3.4.1-4.18.1 | | `libnettle` | SUSE:Linux Enterprise Server for SAP Applications 12 SP3 | All versions | 2.7.1-13.6.1 | | `libnettle` | SUSE:Linux Enterprise Server for SAP Applications 12 SP4 | All versions | 2.7.1-13.6.1 | | `libnettle` | SUSE:Linux Enterprise Server for SAP Applications 12 SP5 | All versions | 2.7.1-13.6.1 | | `libnettle` | SUSE:Linux Enterprise Server for SAP Applications 15 | All versions | 3.4.1-4.18.1 | | `libnettle` | SUSE:Linux Enterprise Server for SAP Applications 15 SP1 | All versions | 3.4.1-4.18.1 | | `libnettle` | SUSE:Linux Enterprise Software Development Kit 12 SP5 | All versions | 2.7.1-13.6.1 | | `libnettle` | SUSE:Manager Proxy 4.0 | All versions | 3.4.1-4.18.1 | | `libnettle` | SUSE:Manager Retail Branch Server 4.0 | All versions | 3.4.1-4.18.1 | | `libnettle` | SUSE:Manager Server 4.0 | All versions | 3.4.1-4.18.1 | | `libnettle` | SUSE:OpenStack Cloud 8 | All versions | 2.7.1-13.6.1 | | `libnettle` | SUSE:OpenStack Cloud 9 | All versions | 2.7.1-13.6.1 | | `libnettle` | SUSE:OpenStack Cloud Crowbar 8 | All versions | 2.7.1-13.6.1 | | `libnettle` | SUSE:OpenStack Cloud Crowbar 9 | All versions | 2.7.1-13.6.1 | | `libnettle` | openSUSE:Leap 15.2 | All versions | 3.4.1-lp152.4.6.1 | | `libnettle` | openSUSE:Leap 15.3 | All versions | 3.4.1-4.18.1 | Products: Debian Debian Linux, Netapp Ontap Select Deploy Administration Utility, Nettle Project Nettle, Redhat Enterprise Linux. ## How do I fix CVE-2021-3580? Apply the vendor's patch. ## Is CVE-2021-3580 being exploited? There is no known exploitation of CVE-2021-3580 in the wild and no public exploit code. ## Other vulnerabilities in Debian Debian Linux - [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild) - [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild) - [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild) - [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild) - [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2021-3580 and fix it if it is affected. What it is: CVE-2021-3580 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 5 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2021-3580 in the wild and no public exploit code. Affected product: Debian Debian Linux. 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-2021-3580/ (Markdown: https://insights.sbomify.com/CVE-2021-3580/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3580 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3580 - OSV: https://osv.dev/vulnerability/CVE-2021-3580 --- From sbomify Insights: https://insights.sbomify.com/CVE-2021-3580/ Summaries are generated and may contain mistakes; the official description above is the record.