# CVE-2018-5743: Limiting simultaneous TCP clients was ineffective > Attackers can bypass TCP connection limits in BIND, causing resource exhaustion and denial of service. - **Severity:** High 7.5 (`CVSS:3.0/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:** 9 Oct 2019 - **Updated:** 17 Sep 2024 - **Also known as:** ALPINE-CVE-2018-5743, DEBIAN-CVE-2018-5743, DLA-1859-1, GHSA-3cr4-c5wq-3ccv, RHSA-2019:1145, RHSA-2019:1294, RHSA-2019:1492, RHSA-2019:2698, RHSA-2019:2977, UBUNTU-CVE-2018-5743, USN-3956-1, USN-3956-2 ## What is CVE-2018-5743? CVE-2018-5743 is a high-severity denial of service vulnerability in F5 Big-Ip Access Policy Manager, published on 9 Oct 2019. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description By design, BIND is intended to limit the number of TCP clients that can be connected at any given time. The number of allowed connections is a tunable parameter which, if unset, defaults to a conservative value for most servers. Unfortunately, the code which was intended to limit the number of simultaneous connections contained an error which could be exploited to grow the number of simultaneous connections beyond this limit. Versions affected: BIND 9.9.0 -> 9.10.8-P1, 9.11.0 -> 9.11.6, 9.12.0 -> 9.12.4, 9.14.0. BIND 9 Supported Preview Edition versions 9.9.3-S1 -> 9.11.5-S3, and 9.11.5-S5. Versions 9.13.0 -> 9.13.7 of the 9.13 development branch are also affected. Versions prior to BIND 9.9.0 have not been evaluated for vulnerability to CVE-2018-5743. Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling) ## Which versions are affected by CVE-2018-5743? It affects 17 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `bind` | Red Hat:enterprise_linux:6::client | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-chroot` | Red Hat:enterprise_linux:6::client | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-debuginfo` | Red Hat:enterprise_linux:6::client | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-devel` | Red Hat:enterprise_linux:6::client | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-libs` | Red Hat:enterprise_linux:6::client | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-sdb` | Red Hat:enterprise_linux:6::client | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-utils` | Red Hat:enterprise_linux:6::client | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind` | Red Hat:enterprise_linux:6::computenode | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-chroot` | Red Hat:enterprise_linux:6::computenode | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-debuginfo` | Red Hat:enterprise_linux:6::computenode | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-devel` | Red Hat:enterprise_linux:6::computenode | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-libs` | Red Hat:enterprise_linux:6::computenode | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-sdb` | Red Hat:enterprise_linux:6::computenode | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-utils` | Red Hat:enterprise_linux:6::computenode | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind` | Red Hat:enterprise_linux:6::server | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-chroot` | Red Hat:enterprise_linux:6::server | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-debuginfo` | Red Hat:enterprise_linux:6::server | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-devel` | Red Hat:enterprise_linux:6::server | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-libs` | Red Hat:enterprise_linux:6::server | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-sdb` | Red Hat:enterprise_linux:6::server | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-utils` | Red Hat:enterprise_linux:6::server | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind` | Red Hat:enterprise_linux:6::workstation | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-chroot` | Red Hat:enterprise_linux:6::workstation | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-debuginfo` | Red Hat:enterprise_linux:6::workstation | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-devel` | Red Hat:enterprise_linux:6::workstation | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-libs` | Red Hat:enterprise_linux:6::workstation | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-sdb` | Red Hat:enterprise_linux:6::workstation | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind-utils` | Red Hat:enterprise_linux:6::workstation | All versions | 32:9.8.2-0.68.rc1.el6_10.3 | | `bind` | Red Hat:enterprise_linux:7::client | All versions | 32:9.9.4-74.el7_6.1 | | `bind-chroot` | Red Hat:enterprise_linux:7::client | All versions | 32:9.9.4-74.el7_6.1 | | `bind-debuginfo` | Red Hat:enterprise_linux:7::client | All versions | 32:9.9.4-74.el7_6.1 | | `bind-devel` | Red Hat:enterprise_linux:7::client | All versions | 32:9.9.4-74.el7_6.1 | | `bind-libs` | Red Hat:enterprise_linux:7::client | All versions | 32:9.9.4-74.el7_6.1 | | `bind-libs-lite` | Red Hat:enterprise_linux:7::client | All versions | 32:9.9.4-74.el7_6.1 | | `bind-license` | Red Hat:enterprise_linux:7::client | All versions | 32:9.9.4-74.el7_6.1 | | `bind-lite-devel` | Red Hat:enterprise_linux:7::client | All versions | 32:9.9.4-74.el7_6.1 | | `bind-pkcs11` | Red Hat:enterprise_linux:7::client | All versions | 32:9.9.4-74.el7_6.1 | | `bind-pkcs11-devel` | Red Hat:enterprise_linux:7::client | All versions | 32:9.9.4-74.el7_6.1 | | `bind-pkcs11-libs` | Red Hat:enterprise_linux:7::client | All versions | 32:9.9.4-74.el7_6.1 | | `bind-pkcs11-utils` | Red Hat:enterprise_linux:7::client | All versions | 32:9.9.4-74.el7_6.1 | Products: F5 Big-Ip Access Policy Manager, F5 Big-Ip Advanced Firewall Manager, F5 Big-Ip Analytics, F5 Big-Ip Application Acceleration Manager, F5 Big-Ip Application Security Manager, F5 Big-Ip Domain Name System, F5 Big-Ip Edge Gateway, F5 Big-Ip Fraud Protection Service, F5 Big-Ip Global Traffic Manager, F5 Big-Ip Link Controller, F5 Big-Ip Local Traffic Manager, F5 Big-Ip Policy Enforcement Manager, F5 Big-Ip Webaccelerator, F5 Big-Iq Centralized Management, F5 Enterprise Manager, F5 Iworkflow, Isc Bind. ## How do I fix CVE-2018-5743? Apply the vendor's patch. ## Is CVE-2018-5743 being exploited? There is no known exploitation of CVE-2018-5743 in the wild and no public exploit code. ## Other vulnerabilities in F5 Big-Ip Access Policy Manager - [CVE-2023-46747](https://insights.sbomify.com/CVE-2023-46747/): F5 BIG-IP Configuration Utility Authentication Bypass (critical 9.8, exploited in the wild) - [CVE-2022-1388](https://insights.sbomify.com/CVE-2022-1388/): F5 BIG-IP Missing Authentication (critical 9.8, exploited in the wild) - [CVE-2021-22986](https://insights.sbomify.com/CVE-2021-22986/): F5 BIG-IP and BIG-IQ Centralized Management iControl REST Remote Code Execution (critical 9.8, exploited in the wild) - [CVE-2021-22991](https://insights.sbomify.com/CVE-2021-22991/): F5 BIG-IP Traffic Management Microkernel Buffer Overflow (critical 9.8, exploited in the wild) - [CVE-2020-5902](https://insights.sbomify.com/CVE-2020-5902/): F5 BIG-IP Traffic Management User Interface (TMUI) Remote Code Execution (critical 9.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2018-5743 and fix it if it is affected. What it is: CVE-2018-5743 is a high-severity denial of service vulnerability in F5 Big-Ip Access Policy Manager, published on 9 Oct 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-2018-5743 in the wild and no public exploit code. Affected product: F5 Big-Ip Access Policy Manager. 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-2018-5743/ (Markdown: https://insights.sbomify.com/CVE-2018-5743/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2018-5743 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-5743 - OSV: https://osv.dev/vulnerability/CVE-2018-5743 --- From sbomify Insights: https://insights.sbomify.com/CVE-2018-5743/ Summaries are generated and may contain mistakes; the official description above is the record.