# CVE-2023-32067: 0-byte UDP payload DoS in c-ares > An attacker can cause a denial of service in applications using c-ares by sending forged zero-length UDP packets, triggering an erroneous connection shutdown. - **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:** 25 May 2023 - **Updated:** 13 Feb 2025 - **Also known as:** ALSA-2023:3559, ALSA-2023:3584, AZL-26913, AZL-26918, AZL-26921, AZL-26937, AZL-26939, AZL-26942, AZL-34782, AZL-43924, CLSA-2026-1787663550, DEBIAN-CVE-2023-32067, ECHO-d868-b924-469d, GHSA-9g78-jv2r-p7vc, OESA-2023-1302, OESA-2023-1311, OESA-2023-1312, OESA-2023-1313, OESA-2023-1314, RHSA-2023:3559, RHSA-2023:3583, RHSA-2023:3584, RHSA-2023:3660, RHSA-2023:3662, RHSA-2023:3665, RHSA-2023:3677, RHSA-2023:3741, RLSA-2023:3559, RLSA-2023:3584, UBUNTU-CVE-2023-32067 ## What is CVE-2023-32067? CVE-2023-32067 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 25 May 2023. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description c-ares is an asynchronous resolver library. c-ares is vulnerable to denial of service. If a target resolver sends a query, the attacker forges a malformed UDP packet with a length of 0 and returns them to the target resolver. The target resolver erroneously interprets the 0 length as a graceful shutdown of the connection. This issue has been patched in version 1.19.1. Weakness: CWE-400 (Uncontrolled Resource Consumption) ## Which versions are affected by CVE-2023-32067? It affects 3 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `c-ares` | AlmaLinux:8 | All versions | 1.13.0-6.el8_8.2 | | `c-ares-devel` | AlmaLinux:8 | All versions | 1.13.0-6.el8_8.2 | | `c-ares` | AlmaLinux:9 | All versions | 1.17.1-5.el9_2.1 | | `c-ares-devel` | AlmaLinux:9 | All versions | 1.17.1-5.el9_2.1 | | `c-ares` | Red Hat:enterprise_linux:7::client | All versions | 0:1.10.0-3.el7_9.1 | | `c-ares-debuginfo` | Red Hat:enterprise_linux:7::client | All versions | 0:1.10.0-3.el7_9.1 | | `c-ares-devel` | Red Hat:enterprise_linux:7::client | All versions | 0:1.10.0-3.el7_9.1 | | `c-ares-debuginfo` | Red Hat:enterprise_linux:7::computenode | All versions | 0:1.10.0-3.el7_9.1 | | `c-ares-devel` | Red Hat:enterprise_linux:7::computenode | All versions | 0:1.10.0-3.el7_9.1 | | `c-ares` | Red Hat:enterprise_linux:7::server | All versions | 0:1.10.0-3.el7_9.1 | | `c-ares-debuginfo` | Red Hat:enterprise_linux:7::server | All versions | 0:1.10.0-3.el7_9.1 | | `c-ares-devel` | Red Hat:enterprise_linux:7::server | All versions | 0:1.10.0-3.el7_9.1 | | `c-ares` | Red Hat:enterprise_linux:7::workstation | All versions | 0:1.10.0-3.el7_9.1 | | `c-ares-debuginfo` | Red Hat:enterprise_linux:7::workstation | All versions | 0:1.10.0-3.el7_9.1 | | `c-ares-devel` | Red Hat:enterprise_linux:7::workstation | All versions | 0:1.10.0-3.el7_9.1 | | `c-ares` | Red Hat:enterprise_linux:8::baseos | All versions | 0:1.13.0-6.el8_8.2 | | `c-ares-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:1.13.0-6.el8_8.2 | | `c-ares-debugsource` | Red Hat:enterprise_linux:8::baseos | All versions | 0:1.13.0-6.el8_8.2 | | `c-ares-devel` | Red Hat:enterprise_linux:8::baseos | All versions | 0:1.13.0-6.el8_8.2 | | `c-ares-debuginfo` | Red Hat:enterprise_linux:9::appstream | All versions | 0:1.17.1-5.el9_2.1 | | `c-ares-debugsource` | Red Hat:enterprise_linux:9::appstream | All versions | 0:1.17.1-5.el9_2.1 | | `c-ares-devel` | Red Hat:enterprise_linux:9::appstream | All versions | 0:1.17.1-5.el9_2.1 | | `c-ares` | Red Hat:enterprise_linux:9::baseos | All versions | 0:1.17.1-5.el9_2.1 | | `c-ares-debuginfo` | Red Hat:enterprise_linux:9::baseos | All versions | 0:1.17.1-5.el9_2.1 | | `c-ares-debugsource` | Red Hat:enterprise_linux:9::baseos | All versions | 0:1.17.1-5.el9_2.1 | | `c-ares` | Red Hat:rhel_aus:8.2::baseos | All versions | 0:1.13.0-5.el8_2.1 | | `c-ares-debuginfo` | Red Hat:rhel_aus:8.2::baseos | All versions | 0:1.13.0-5.el8_2.1 | | `c-ares-debugsource` | Red Hat:rhel_aus:8.2::baseos | All versions | 0:1.13.0-5.el8_2.1 | | `c-ares-devel` | Red Hat:rhel_aus:8.2::baseos | All versions | 0:1.13.0-5.el8_2.1 | | `c-ares` | Red Hat:rhel_aus:8.4::baseos | All versions | 0:1.13.0-5.el8_4.2 | | `c-ares-debuginfo` | Red Hat:rhel_aus:8.4::baseos | All versions | 0:1.13.0-5.el8_4.2 | | `c-ares-debugsource` | Red Hat:rhel_aus:8.4::baseos | All versions | 0:1.13.0-5.el8_4.2 | | `c-ares-devel` | Red Hat:rhel_aus:8.4::baseos | All versions | 0:1.13.0-5.el8_4.2 | | `c-ares` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:1.13.0-5.el8_1.1 | | `c-ares-debuginfo` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:1.13.0-5.el8_1.1 | | `c-ares-debugsource` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:1.13.0-5.el8_1.1 | | `c-ares-devel` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:1.13.0-5.el8_1.1 | | `c-ares` | Red Hat:rhel_e4s:8.2::baseos | All versions | 0:1.13.0-5.el8_2.1 | | `c-ares-debuginfo` | Red Hat:rhel_e4s:8.2::baseos | All versions | 0:1.13.0-5.el8_2.1 | | `c-ares-debugsource` | Red Hat:rhel_e4s:8.2::baseos | All versions | 0:1.13.0-5.el8_2.1 | Products: C-Ares Project C-Ares, Debian Debian Linux, Fedoraproject Fedora. ## How do I fix CVE-2023-32067? Upgrade to a fixed version. ## Is CVE-2023-32067 being exploited? There is no known exploitation of CVE-2023-32067 in the wild and no public exploit code. ## Other vulnerabilities in Debian Debian Linux - [CVE-2022-4904](https://insights.sbomify.com/CVE-2022-4904/): Memory corruption in c-ares (high 8.6) - [CVE-2020-8277](https://insights.sbomify.com/CVE-2020-8277/): Uncontrolled Resource Consumption in node (high 7.5) - [CVE-2023-31147](https://insights.sbomify.com/CVE-2023-31147/): Insufficient randomness in generation of DNS query IDs in c-ares (medium 5.9) - [CVE-2021-3672](https://insights.sbomify.com/CVE-2021-3672/): Other in c-ares (medium 5.6) - [CVE-2023-31130](https://insights.sbomify.com/CVE-2023-31130/): Buffer Underwrite in ares_inet_net_pton() (medium 4.1) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2023-32067 and fix it if it is affected. What it is: CVE-2023-32067 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 25 May 2023. 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-2023-32067 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-2023-32067/ (Markdown: https://insights.sbomify.com/CVE-2023-32067/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2023-32067 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-32067 - OSV: https://osv.dev/vulnerability/CVE-2023-32067 --- From sbomify Insights: https://insights.sbomify.com/CVE-2023-32067/ Summaries are generated and may contain mistakes; the official description above is the record.