An issue was discovered in Squid before 4.10. Due to incorrect input validation, the NTLM authentication credentials parser in ext_lm_group_acl may write to memory outside the credentials buffer. On systems with memory access protections, this can result in the helper process being terminated unexpectedly. This leads to the Squid process also terminating and a denial of service for all clients using the proxy.

Affected: Ubuntu:16.04:LTS: squid3, Ubuntu:18.04:LTS: squid3

Jeriko One discovered that Squid incorrectly handled memory when connected to an FTP server. A remote attacker could possibly use this issue to obtain sensitive information from Squid memory. (CVE-2019-12528)

Regis Leroy discovered that Squid incorrectly handled certain HTTP requests. A remote attacker could possibly use this issue to access server resources prohibited by earlier security filters. (CVE-2020-8449)

Guido Vranken discovered that Squid incorrectly handled certain buffer operations when acting as a reverse proxy. A remote attacker could use this issue to cause Squid to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2020-8450)

Aaron Costello discovered that Squid incorrectly handled certain NTLM authentication credentials. A remote attacker could possibly use this issue to cause Squid to crash, resulting in a denial of service. (CVE-2020-8517)