Arch Linux Security Advisory ASA-201908-13 ========================================== Severity: Medium Date : 2019-08-16 CVE-ID : CVE-2019-9511 CVE-2019-9513 CVE-2019-9516 Package : nginx Type : denial of service Remote : Yes Link : https://security.archlinux.org/AVG-1023 Summary ======= The package nginx before version 1.16.1-1 is vulnerable to denial of service. Resolution ========== Upgrade to 1.16.1-1. # pacman -Syu "nginx>=1.16.1-1" The problems have been fixed upstream in version 1.16.1. Workaround ========== Disable http/2 support. Description =========== - CVE-2019-9511 (denial of service) An issue has been found in several HTTP/2 implementations, where the attacker requests a large amount of data from a specified resource over multiple streams. They manipulate window size and stream priority to force the server to queue the data in 1-byte chunks. Depending on how efficiently this data is queued, this can consume excess CPU, memory, or both, potentially leading to a denial of service. - CVE-2019-9513 (denial of service) An issue has been found in several HTTP/2 implementations, where the attacker creates multiple request streams and continually shuffles the priority of the streams in a way that causes substantial churn to the priority tree. This can consume excess CPU, potentially leading to a denial of service. - CVE-2019-9516 (denial of service) An issue has been found in several HTTP/2 implementations, where the attacker sends a stream of headers with a 0-length header name and 0-length header value, optionally Huffman encoded into 1-byte or greater headers. Some implementations allocate memory for these headers and keep the allocation alive until the session dies. This can consume excess memory, potentially leading to a denial of service. Impact ====== A remote attacker is able cause a denial of service by sending a specially crafted packet. References ========== https://mailman.nginx.org/pipermail/nginx-announce/2019/000249.html https://github.com/Netflix/security-bulletins/blob/master/advisories/third-p... https://github.com/nginx/nginx/commit/a987f81dd19210bc30b62591db331e31d3d740... https://github.com/nginx/nginx/commit/5ae726912654da10a9a81b2c8436829f3e94f6... https://github.com/nginx/nginx/commit/6dfbc8b1c2116f362bb871efebbf9df576738e... https://security.archlinux.org/CVE-2019-9511 https://security.archlinux.org/CVE-2019-9513 https://security.archlinux.org/CVE-2019-9516