--- title: "CVE-2019-9518\n | Ubuntu" description: Ubuntu is an open source software operating system that runs from the desktop, to the cloud, to all your internet connected things. url: https://ubuntu.com/security/CVE-2019-9518?format=md keywords: index, follow --- # CVE-2019-9518 Publication date 13 August 2019 Last updated 11 July 2025 --- Ubuntu priority **Medium** [Why this priority?](https://ubuntu.com/security/cves/about#priority ) ## Cvss 3 Severity Score **7.5 · High** [Score breakdown](https://ubuntu.com/security/CVE-2019-9518?format=md#impact-score) Toggle side navigation ## Description Some HTTP/2 implementations are vulnerable to a flood of empty frames, potentially leading to a denial of service. The attacker sends a stream of frames with an empty payload and without the end-of-stream flag. These frames can be DATA, HEADERS, CONTINUATION and/or PUSH\_PROMISE. The peer spends time processing each frame disproportionate to attack bandwidth. This can consume excess CPU. ### From the Ubuntu Security Team It was discovered that Netty incorrectly implements HTTP/2. An attacker could possibly use this issue to cause a denial of service. ## Status Show unmaintained releases | Package | Ubuntu Release | Status | | --- | --- | --- | | netty | 26.04 LTS resolute | Not affected | | 25.10 questing | Not affected | | 25.04 plucky | Not affected | | 24.10 oracular | Not affected | | 24.04 LTS noble | Not affected | | 23.10 mantic | Ignored end of life, was needed | | 23.04 lunar | Ignored end of life, was needed | | 22.10 kinetic | Ignored end of life, was needed | | 22.04 LTS jammy | Not affected | | 21.10 impish | Ignored end of life | | 21.04 hirsute | Ignored end of life | | 20.10 groovy | Ignored end of life | | 20.04 LTS focal | Not affected | | 19.10 eoan | Ignored end of life | | 19.04 disco | Ignored end of life | | 18.04 LTS bionic | Fixed 1:4.1.7-4ubuntu0.1+esm1 Ubuntu Pro | | 16.04 LTS xenial | Not affected | | 14.04 LTS trusty | Not affected | | trafficserver | 26.04 LTS resolute | Not in release | | 25.10 questing | Not affected | | 25.04 plucky | Ignored end of life, was needs-triage | | 24.10 oracular | Ignored end of life, was needs-triage | | 24.04 LTS noble | Not affected | | 23.10 mantic | Ignored end of life, was needs-triage | | 23.04 lunar | Ignored end of life, was needs-triage | | 22.10 kinetic | Ignored end of life, was needs-triage | | 22.04 LTS jammy | Not affected | | 21.10 impish | Ignored end of life | | 21.04 hirsute | Ignored end of life | | 20.10 groovy | Ignored end of life | | 20.04 LTS focal | Not affected | | 18.04 LTS bionic | Vulnerable | | 16.04 LTS xenial | Not affected | | 14.04 LTS trusty | Not in release | --- * [How can I get the fixes?](https://ubuntu.com/security/cves/about#security) * [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses) ### Get expanded security coverage with Ubuntu Pro Reduce your average CVE exposure time from 98 days to 1 day with expanded CVE patching, ten-years security maintenance and optional support for the full stack of open-source applications. Free for personal use. [Get Ubuntu Pro](https://ubuntu.com/pro) [30-day free trial](https://ubuntu.com/pro/free-trial) ## Severity score breakdown CVSS version: CVSS v3.0 **Base score** 7.5 · High * Base metrics | Parameter | Value | | --- | --- | | Attack vector | Network | | Attack complexity | Low | | Privileges required | None | | User interaction | None | | Scope | Unchanged | | Confidentiality impact | None | | Integrity impact | None | | Availability impact | High | * Scores | Parameter | Value | | --- | --- | | Base score | 7.5 · High | | Exploitability score | - | | Impact score | - | **Vector:** CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H ## References * [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-9518) * [NVD](https://nvd.nist.gov/vuln/detail/CVE-2019-9518) * [Launchpad](https://launchpad.net/bugs/cve/CVE-2019-9518) * [Debian](https://security-tracker.debian.org/tracker/CVE-2019-9518) ### Related Ubuntu Security Notices (USN) + [USN-4866-1](https://usn.ubuntu.com/USN-4866-1) + Netty vulnerabilities + 29 June 2021 ### Other references * * * *