CVE-2019-12519

Se detectó un problema en Squid versiones hasta 4.7. Cuando se maneja la etiqueta esi:when cuando ESI está habilitado, Squid llama a la función ESIExpression::Evaluate. Esta función usa un búfer de pila fijado para contener la expresión mientras se está evaluando. Cuando de procesa la expresión, podría evaluar la parte superior de la pila o agregar un nuevo miembro en la pila. Cuando se agrega un nuevo miembro, no se realiza ninguna comprobación para asegurar que la pila no se desborde.

A flaw was found in Squid through version 4.7. When handling the tag esi:when, when ESI is enabled, Squid calls the ESIExpression::Evaluate function which uses a fixed stack buffer to hold the expression. While processing the expression, there is no check to ensure that the stack won't overflow. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Jeriko One discovered that Squid incorrectly handled certain Edge Side Includes responses. A malicious remote server could cause Squid to crash, possibly poison the cache, or possibly execute arbitrary code. It was discovered that Squid incorrectly handled the hostname parameter to cachemgr.cgi when certain browsers are used. A remote attacker could possibly use this issue to inject HTML or invalid characters in the hostname parameter. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 19.10. Various other issues were also addressed.