# CVE-2019-11478: SACK can cause extensive memory use via fragmented resend queue > A remote attacker can cause a denial of service by exploiting TCP SACK handling to exhaust memory in the Linux kernel. - **Severity:** Medium 5.3 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 18 Jun 2019 - **Updated:** 16 Sep 2024 - **Also known as:** DEBIAN-CVE-2019-11478, GHSA-xh2h-cw6h-x9h5, SUSE-SU-2019:1888-1, SUSE-SU-2019:1935-1, UBUNTU-CVE-2019-11478 ## What is CVE-2019-11478? CVE-2019-11478 is a medium-severity denial of service vulnerability in Canonical Ubuntu Linux, published on 18 Jun 2019. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description Jonathan Looney discovered that the TCP retransmission queue implementation in tcp_fragment in the Linux kernel could be fragmented when handling certain TCP Selective Acknowledgment (SACK) sequences. A remote attacker could use this to cause a denial of service. This has been fixed in stable kernel releases 4.4.182, 4.9.182, 4.14.127, 4.19.52, 5.1.11, and is fixed in commit f070ef2ac66716357066b683fb0baf55f8191a2e. Weakness: CWE-400 (Uncontrolled Resource Consumption), CWE-770 (Allocation of Resources Without Limits or Throttling) ## Which versions are affected by CVE-2019-11478? It affects 24 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `kgraft-patch-SLE12-SP4_Update_5` | SUSE:Linux Enterprise Live Patching 12 SP4 | All versions | 2-2.1 | | `kernel-livepatch-SLE15_Update_11` | SUSE:Linux Enterprise Live Patching 15 | All versions | 2-2.1 | | `kernel-livepatch-SLE15-SP1_Update_1` | SUSE:Linux Enterprise Live Patching 15 SP1 | All versions | 3-2.1 | | `kernel-livepatch-SLE15-SP1_Update_2` | SUSE:Linux Enterprise Live Patching 15 SP1 | All versions | 2-2.1 | | `kgraft-patch-SLE12-SP1_Update_34` | SUSE:Linux Enterprise Server 12 SP1-LTSS | All versions | 3-2.1 | | `kgraft-patch-SLE12-SP2_Update_30` | SUSE:Linux Enterprise Server 12 SP2-LTSS | All versions | 3-2.1 | | `kgraft-patch-SLE12-SP3_Update_26` | SUSE:Linux Enterprise Server 12 SP3-LTSS | All versions | 3-2.1 | | `kgraft-patch-SLE12-SP1_Update_34` | SUSE:Linux Enterprise Server for SAP Applications 12 SP1 | All versions | 3-2.1 | | `kgraft-patch-SLE12-SP2_Update_30` | SUSE:Linux Enterprise Server for SAP Applications 12 SP2 | All versions | 3-2.1 | | `kgraft-patch-SLE12-SP3_Update_26` | SUSE:Linux Enterprise Server for SAP Applications 12 SP3 | All versions | 3-2.1 | Products: Canonical Ubuntu Linux, 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 Traffix Signaling Delivery Controller, Ivanti Connect Secure, Linux kernel, Pulsesecure Pulse Policy Secure, Pulsesecure Pulse Secure Virtual Application Delivery Controller, Redhat Enterprise Linux and 4 more. ## How do I fix CVE-2019-11478? Apply the vendor's patch. ## Is CVE-2019-11478 being exploited? There is no known exploitation of CVE-2019-11478 in the wild and no public exploit code. ## Other vulnerabilities in Canonical Ubuntu Linux - [CVE-2020-11651](https://insights.sbomify.com/CVE-2020-11651/): SaltStack Salt Authentication Bypass (critical 9.8, exploited in the wild) - [CVE-2020-7247](https://insights.sbomify.com/CVE-2020-7247/): OpenSMTPD Remote Code Execution (critical 9.8, exploited in the wild) - [CVE-2019-16928](https://insights.sbomify.com/CVE-2019-16928/): Exim Out-of-bounds Write (critical 9.8, exploited in the wild) - [CVE-2018-6789](https://insights.sbomify.com/CVE-2018-6789/): Exim Buffer Overflow (critical 9.8, exploited in the wild) - [CVE-2015-2590](https://insights.sbomify.com/CVE-2015-2590/): Oracle Java SE and Java SE Embedded Remote Code Execution (critical 9.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2019-11478 and fix it if it is affected. What it is: CVE-2019-11478 is a medium-severity denial of service vulnerability in Canonical Ubuntu Linux, published on 18 Jun 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-2019-11478 in the wild and no public exploit code. Affected product: Canonical Ubuntu 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-2019-11478/ (Markdown: https://insights.sbomify.com/CVE-2019-11478/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2019-11478 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-11478 - OSV: https://osv.dev/vulnerability/CVE-2019-11478 --- From sbomify Insights: https://insights.sbomify.com/CVE-2019-11478/ Summaries are generated and may contain mistakes; the official description above is the record.