Arch Linux Security Advisory ASA-201710-2 ========================================= Severity: Low Date : 2017-10-05 CVE-ID : CVE-2017-1000254 Package : curl Type : denial of service Remote : Yes Link : https://security.archlinux.org/AVG-422 Summary ======= The package curl before version 7.56.0-1 is vulnerable to denial of service. Resolution ========== Upgrade to 7.56.0-1. # pacman -Syu "curl>=7.56.0-1" The problem has been fixed upstream in version 7.56.0. Workaround ========== None. Description =========== When libcurl connects to an FTP server and successfully logs in (anonymous or not), it asks the server for the current directory with the `PWD` command. The server then responds with a 257 response containing the path, inside double quotes. The returned path name is then kept by libcurl for subsequent uses. Due to a flaw in the string parser for this directory name, a directory name passed like this but without a closing double quote would lead to libcurl not adding a trailing NUL byte to the buffer holding the name. When libcurl would then later access the string, it could read beyond the allocated heap buffer and crash or wrongly access data beyond the buffer, thinking it was part of the path. A malicious server could abuse this fact and effectively prevent libcurl-based clients to work with it - the PWD command is always issued on new FTP connections and the mistake has a high chance of causing a segfault. Impact ====== A malicious server can cause libcurl to segfault when connecting via FTP leading to denial of service. References ========== https://curl.haxx.se/docs/adv_20171004.html https://curl.haxx.se/CVE-2017-1000254.patch https://github.com/curl/curl/commit/5ff2c5ff25750aba1a8f64fbcad8e5b891512584 https://security.archlinux.org/CVE-2017-1000254