========================================================================== Ubuntu Security Notice USN-4446-1 August 03, 2020 squid3 vulnerabilities ========================================================================== A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 18.04 LTS - Ubuntu 16.04 LTS Summary: Several security issues were fixed in Squid. Software Description: - squid3: Web proxy cache server Details: Jeriko One discovered that Squid incorrectly handled caching certain requests. A remote attacker could possibly use this issue to perform cache-injection attacks or gain access to reverse proxy features such as ESI. (CVE-2019-12520) Jeriko One and Kristoffer Danielsson discovered that Squid incorrectly handled certain URN requests. A remote attacker could possibly use this issue to bypass access checks. (CVE-2019-12523) Jeriko One discovered that Squid incorrectly handled URL decoding. A remote attacker could possibly use this issue to bypass certain rule checks. (CVE-2019-12524) Jeriko One and Kristoffer Danielsson discovered that Squid incorrectly handled input validation. A remote attacker could use this issue to cause Squid to crash, resulting in a denial of service. (CVE-2019-18676) Update instructions: The problem can be corrected by updating your system to the following package versions: Ubuntu 18.04 LTS: squid 3.5.27-1ubuntu1.7 Ubuntu 16.04 LTS: squid 3.5.12-1ubuntu7.12 In general, a standard system update will make all the necessary changes. References: https://usn.ubuntu.com/4446-1 CVE-2019-12520, CVE-2019-12523, CVE-2019-12524, CVE-2019-18676 Package Information: https://launchpad.net/ubuntu/+source/squid3/3.5.27-1ubuntu1.7 https://launchpad.net/ubuntu/+source/squid3/3.5.12-1ubuntu7.12