# CVE-2019-6477: TCP-pipelined queries can bypass tcp-clients limit > Attackers can cause denial of service in BIND9 by sending TCP-pipelined queries that exhaust server resources, leading to unresponsiveness. - **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:** 26 Nov 2019 - **Updated:** 16 Sep 2024 - **Also known as:** ALPINE-CVE-2019-6477, DEBIAN-CVE-2019-6477, GHSA-6q2x-892r-7qm4, RHSA-2020:1845, UBUNTU-CVE-2019-6477, USN-4197-1 ## What is CVE-2019-6477? CVE-2019-6477 is a high-severity denial of service vulnerability in Fedoraproject Fedora, published on 26 Nov 2019. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description With pipelining enabled each incoming query on a TCP connection requires a similar resource allocation to a query received via UDP or via TCP without pipelining enabled. A client using a TCP-pipelined connection to a server could consume more resources than the server has been provisioned to handle. When a TCP connection with a large number of pipelined queries is closed, the load on the server releasing these multiple resources can cause it to become unresponsive, even for queries that can be answered authoritatively or from cache. (This is most likely to be perceived as an intermittent server problem). Weakness: CWE-400 (Uncontrolled Resource Consumption) ## Which versions are affected by CVE-2019-6477? It affects 2 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `bind` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-chroot` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-debugsource` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-devel` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-export-libs-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-libs` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-libs-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-libs-lite` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-libs-lite-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-license` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-lite-devel` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-pkcs11` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-pkcs11-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-pkcs11-devel` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-pkcs11-libs` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-pkcs11-libs-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-pkcs11-utils` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-pkcs11-utils-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-sdb` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-sdb-chroot` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-sdb-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-utils` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind-utils-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `python3-bind` | Red Hat:enterprise_linux:8::appstream | All versions | 32:9.11.13-3.el8 | | `bind` | Red Hat:enterprise_linux:8::baseos | All versions | 32:9.11.13-3.el8 | | `bind-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 32:9.11.13-3.el8 | | `bind-debugsource` | Red Hat:enterprise_linux:8::baseos | All versions | 32:9.11.13-3.el8 | | `bind-export-devel` | Red Hat:enterprise_linux:8::baseos | All versions | 32:9.11.13-3.el8 | | `bind-export-libs` | Red Hat:enterprise_linux:8::baseos | All versions | 32:9.11.13-3.el8 | | `bind-export-libs-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 32:9.11.13-3.el8 | | `bind-libs-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 32:9.11.13-3.el8 | | `bind-libs-lite-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 32:9.11.13-3.el8 | | `bind-pkcs11-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 32:9.11.13-3.el8 | | `bind-pkcs11-libs-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 32:9.11.13-3.el8 | | `bind-pkcs11-utils-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 32:9.11.13-3.el8 | | `bind-sdb-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 32:9.11.13-3.el8 | | `bind-utils-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 32:9.11.13-3.el8 | Products: Fedoraproject Fedora, Isc Bind. ## How do I fix CVE-2019-6477? Apply the vendor's patch. ## Is CVE-2019-6477 being exploited? There is no known exploitation of CVE-2019-6477 in the wild and no public exploit code. ## Other vulnerabilities in Fedoraproject Fedora - [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild) - [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild) - [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild) - [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild) - [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2019-6477 and fix it if it is affected. What it is: CVE-2019-6477 is a high-severity denial of service vulnerability in Fedoraproject Fedora, published on 26 Nov 2019. 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-2019-6477 in the wild and no public exploit code. Affected product: Fedoraproject Fedora. 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-2019-6477/ (Markdown: https://insights.sbomify.com/CVE-2019-6477/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2019-6477 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-6477 - OSV: https://osv.dev/vulnerability/CVE-2019-6477 --- From sbomify Insights: https://insights.sbomify.com/CVE-2019-6477/ Summaries are generated and may contain mistakes; the official description above is the record.