# CVE-2020-35498: Denial of service in openvswitch > A malicious user can cause a denial of service in Open vSwitch by sending crafted packets that create overly wide kernel megaflows. - **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:** 11 Feb 2021 - **Updated:** 23 Apr 2025 - **Also known as:** DEBIAN-CVE-2020-35498, DSA-4852-1, GHSA-9978-p96m-85pj, SUSE-SU-2021:0436-1, SUSE-SU-2021:0439-1, SUSE-SU-2021:0440-1, SUSE-SU-2021:0446-1, SUSE-SU-2021:0451-1, SUSE-SU-2021:0479-1, SUSE-SU-2022:3384-1, UBUNTU-CVE-2020-35498, USN-4729-1, openSUSE-SU-2021:0283-1 ## What is CVE-2020-35498? CVE-2020-35498 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 11 Feb 2021. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description A vulnerability was found in openvswitch. A limitation in the implementation of userspace packet parsing can allow a malicious user to send a specially crafted packet causing the resulting megaflow in the kernel to be too wide, potentially causing a denial of service. The highest threat from this vulnerability is to system availability. Weakness: CWE-400 (Uncontrolled Resource Consumption) ## Which versions are affected by CVE-2020-35498? It affects 3 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `openvswitch` | SUSE:Enterprise Storage 5 | All versions | 2.7.12-3.39.1 | | `openvswitch` | SUSE:Enterprise Storage 6 | All versions | 2.11.5-3.15.3 | | `openvswitch` | SUSE:HPE Helion OpenStack 8 | All versions | 2.7.12-3.39.1 | | `openvswitch` | SUSE:Linux Enterprise High Performance Computing 15 SP1-ESPOS | All versions | 2.11.5-3.15.3 | | `openvswitch` | SUSE:Linux Enterprise High Performance Computing 15 SP1-LTSS | All versions | 2.11.5-3.15.3 | | `openvswitch` | SUSE:Linux Enterprise High Performance Computing 15-ESPOS | All versions | 2.11.5-6.33.3 | | `openvswitch` | SUSE:Linux Enterprise High Performance Computing 15-LTSS | All versions | 2.11.5-6.33.3 | | `openvswitch` | SUSE:Linux Enterprise Module for Package Hub 15 SP2 | All versions | 2.11.5-3.15.3 | | `openvswitch` | SUSE:Linux Enterprise Module for Package Hub 15 SP2 | All versions | 2.13.2-9.14.1 | | `openvswitch` | SUSE:Linux Enterprise Module for Server Applications 15 SP2 | All versions | 2.13.2-9.14.1 | | `openvswitch` | SUSE:Linux Enterprise Server 12 SP2-BCL | All versions | 2.5.11-25.29.1 | | `openvswitch-dpdk` | SUSE:Linux Enterprise Server 12 SP2-BCL | All versions | 2.5.11-25.29.1 | | `openvswitch` | SUSE:Linux Enterprise Server 12 SP2-LTSS | All versions | 2.5.11-25.29.1 | | `openvswitch-dpdk` | SUSE:Linux Enterprise Server 12 SP2-LTSS | All versions | 2.5.11-25.29.1 | | `openvswitch` | SUSE:Linux Enterprise Server 12 SP3-BCL | All versions | 2.7.12-3.39.1 | | `openvswitch` | SUSE:Linux Enterprise Server 12 SP3-LTSS | All versions | 2.7.12-3.39.1 | | `openvswitch` | SUSE:Linux Enterprise Server 12 SP4-LTSS | All versions | 2.8.10-4.26.1 | | `openvswitch` | SUSE:Linux Enterprise Server 12 SP5 | All versions | 2.11.5-3.9.1 | | `openvswitch` | SUSE:Linux Enterprise Server 15 SP1-BCL | All versions | 2.11.5-3.15.3 | | `openvswitch` | SUSE:Linux Enterprise Server 15 SP1-LTSS | All versions | 2.11.5-3.15.3 | | `openvswitch` | SUSE:Linux Enterprise Server 15-LTSS | All versions | 2.11.5-6.33.3 | | `openvswitch` | SUSE:Linux Enterprise Server for SAP Applications 12 SP2 | All versions | 2.5.11-25.29.1 | | `openvswitch-dpdk` | SUSE:Linux Enterprise Server for SAP Applications 12 SP2 | All versions | 2.5.11-25.29.1 | | `openvswitch` | SUSE:Linux Enterprise Server for SAP Applications 12 SP3 | All versions | 2.7.12-3.39.1 | | `openvswitch` | SUSE:Linux Enterprise Server for SAP Applications 12 SP4 | All versions | 2.8.10-4.26.1 | | `openvswitch` | SUSE:Linux Enterprise Server for SAP Applications 12 SP5 | All versions | 2.11.5-3.9.1 | | `openvswitch` | SUSE:Linux Enterprise Server for SAP Applications 15 | All versions | 2.11.5-6.33.3 | | `openvswitch` | SUSE:Linux Enterprise Server for SAP Applications 15 SP1 | All versions | 2.11.5-3.15.3 | | `openvswitch` | SUSE:Manager Proxy 4.0 | All versions | 2.11.5-3.15.3 | | `openvswitch` | SUSE:Manager Retail Branch Server 4.0 | All versions | 2.11.5-3.15.3 | | `openvswitch` | SUSE:Manager Server 4.0 | All versions | 2.11.5-3.15.3 | | `openvswitch` | SUSE:OpenStack Cloud 7 | All versions | 2.5.11-25.29.1 | | `openvswitch-dpdk` | SUSE:OpenStack Cloud 7 | All versions | 2.5.11-25.29.1 | | `openvswitch` | SUSE:OpenStack Cloud 8 | All versions | 2.7.12-3.39.1 | | `openvswitch` | SUSE:OpenStack Cloud 9 | All versions | 2.8.10-4.26.1 | | `openvswitch` | SUSE:OpenStack Cloud Crowbar 8 | All versions | 2.7.12-3.39.1 | | `openvswitch` | SUSE:OpenStack Cloud Crowbar 9 | All versions | 2.8.10-4.26.1 | | `openvswitch` | openSUSE:Leap 15.2 | All versions | 2.13.2-lp152.3.12.1 | Products: Debian Debian Linux, Fedoraproject Fedora, Openvswitch Openvswitch. ## How do I fix CVE-2020-35498? Apply the vendor's patch. ## Is CVE-2020-35498 being exploited? There is no known exploitation of CVE-2020-35498 in the wild and no public exploit code. Public exploit code: - Flag the cve-2020-35498 attack (github_poc): https://github.com/freddierice/cve-2020-35498-flag ## 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-2020-35498 and fix it if it is affected. What it is: CVE-2020-35498 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 11 Feb 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-2020-35498 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-2020-35498/ (Markdown: https://insights.sbomify.com/CVE-2020-35498/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2020-35498 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-35498 - OSV: https://osv.dev/vulnerability/CVE-2020-35498 --- From sbomify Insights: https://insights.sbomify.com/CVE-2020-35498/ Summaries are generated and may contain mistakes; the official description above is the record.