# CVE-2021-20322: Information disclosure in kernel > Remote attackers can bypass UDP source port randomization to scan open ports, compromising confidentiality and potentially integrity. - **Severity:** High 7.4 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 18 Feb 2022 - **Updated:** 30 Jul 2026 - **Also known as:** DEBIAN-CVE-2021-20322, GHSA-x37m-35qq-p254, SUSE-SU-2021:4057-1, SUSE-SU-2021:4075-1, UBUNTU-CVE-2021-20322 ## What is CVE-2021-20322? CVE-2021-20322 is a high-severity vulnerability in Debian Debian Linux, published on 18 Feb 2022. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description A flaw in the processing of received ICMP errors (ICMP fragment needed and ICMP redirect) in the Linux kernel functionality was found to allow the ability to quickly scan open UDP ports. This flaw allows an off-path remote user to effectively bypass the source port UDP randomization. The highest threat from this vulnerability is to confidentiality and possibly integrity, because software that relies on UDP source port randomization are indirectly affected as well. Weakness: CWE-330 (Use of Insufficiently Random Values) ## Which versions are affected by CVE-2021-20322? It affects 21 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `kernel-livepatch-SLE15-SP2_Update_12` | SUSE:Linux Enterprise Live Patching 15 SP2 | All versions | 9-2.1 | | `kernel-livepatch-SLE15-SP2_Update_13` | SUSE:Linux Enterprise Live Patching 15 SP2 | All versions | 9-2.1 | | `kernel-livepatch-SLE15-SP2_Update_14` | SUSE:Linux Enterprise Live Patching 15 SP2 | All versions | 7-2.1 | | `kernel-livepatch-SLE15-SP2_Update_16` | SUSE:Linux Enterprise Live Patching 15 SP2 | All versions | 7-2.1 | | `kernel-livepatch-SLE15-SP2_Update_17` | SUSE:Linux Enterprise Live Patching 15 SP2 | All versions | 6-2.1 | | `kernel-livepatch-SLE15-SP2_Update_18` | SUSE:Linux Enterprise Live Patching 15 SP2 | All versions | 5-2.1 | | `kernel-livepatch-SLE15-SP2_Update_19` | SUSE:Linux Enterprise Live Patching 15 SP2 | All versions | 3-2.1 | | `kernel-livepatch-SLE15-SP2_Update_20` | SUSE:Linux Enterprise Live Patching 15 SP2 | All versions | 3-2.1 | | `kernel-livepatch-SLE15-SP2_Update_21` | SUSE:Linux Enterprise Live Patching 15 SP2 | All versions | 2-2.1 | | `kernel-livepatch-SLE15-SP3_Update_1` | SUSE:Linux Enterprise Live Patching 15 SP3 | All versions | 7-2.1 | | `kernel-livepatch-SLE15-SP3_Update_2` | SUSE:Linux Enterprise Live Patching 15 SP3 | All versions | 7-2.1 | | `kernel-livepatch-SLE15-SP3_Update_3` | SUSE:Linux Enterprise Live Patching 15 SP3 | All versions | 7-2.1 | | `kernel-livepatch-SLE15-SP3_Update_4` | SUSE:Linux Enterprise Live Patching 15 SP3 | All versions | 6-2.1 | | `kernel-livepatch-SLE15-SP3_Update_5` | SUSE:Linux Enterprise Live Patching 15 SP3 | All versions | 5-2.1 | | `kernel-livepatch-SLE15-SP3_Update_6` | SUSE:Linux Enterprise Live Patching 15 SP3 | All versions | 3-2.1 | | `kernel-livepatch-SLE15-SP3_Update_7` | SUSE:Linux Enterprise Live Patching 15 SP3 | All versions | 3-2.1 | | `kernel-livepatch-SLE15-SP3_Update_9` | SUSE:Linux Enterprise Live Patching 15 SP3 | All versions | 2-2.1 | | `kgraft-patch-SLE12-SP3_Update_37` | SUSE:Linux Enterprise Server 12 SP3-LTSS | All versions | 13-2.2 | | `kgraft-patch-SLE12-SP3_Update_38` | SUSE:Linux Enterprise Server 12 SP3-LTSS | All versions | 12-2.2 | | `kgraft-patch-SLE12-SP3_Update_39` | SUSE:Linux Enterprise Server 12 SP3-LTSS | All versions | 9-2.1 | | `kgraft-patch-SLE12-SP3_Update_40` | SUSE:Linux Enterprise Server 12 SP3-LTSS | All versions | 6-2.1 | | `kgraft-patch-SLE12-SP3_Update_37` | SUSE:Linux Enterprise Server for SAP Applications 12 SP3 | All versions | 13-2.2 | | `kgraft-patch-SLE12-SP3_Update_38` | SUSE:Linux Enterprise Server for SAP Applications 12 SP3 | All versions | 12-2.2 | | `kgraft-patch-SLE12-SP3_Update_39` | SUSE:Linux Enterprise Server for SAP Applications 12 SP3 | All versions | 9-2.1 | | `kgraft-patch-SLE12-SP3_Update_40` | SUSE:Linux Enterprise Server for SAP Applications 12 SP3 | All versions | 6-2.1 | Products: Debian Debian Linux, Fedoraproject Fedora, Linux kernel, Netapp Active Iq Unified Manager, Netapp Aff A700s Firmware, Netapp Aff Baseboard Management Controller Firmware, Netapp E-Series Santricity Os Controller, Netapp Fas Baseboard Management Controller Firmware, Netapp H300e Firmware, Netapp H300s Firmware, Netapp H410s Firmware, Netapp H500e Firmware, Netapp H500s Firmware, Netapp H700e Firmware, Netapp H700s Firmware, Netapp Hci Compute Node Firmware, Netapp Solidfire\, Enterprise Sds \& Hci Storage Node, Netapp Solidfire \& Hci Management Node, Oracle Communications Cloud Native Core Binding Support Function, Oracle Communications Cloud Native Core Network Exposure Function and 1 more. ## How do I fix CVE-2021-20322? Apply the vendor's patch. ## Is CVE-2021-20322 being exploited? There is no known exploitation of CVE-2021-20322 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-2021-20322 and fix it if it is affected. What it is: CVE-2021-20322 is a high-severity vulnerability in Debian Debian Linux, published on 18 Feb 2022. 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-2021-20322 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-2021-20322/ (Markdown: https://insights.sbomify.com/CVE-2021-20322/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20322 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20322 - OSV: https://osv.dev/vulnerability/CVE-2021-20322 --- From sbomify Insights: https://insights.sbomify.com/CVE-2021-20322/ Summaries are generated and may contain mistakes; the official description above is the record.