CVE-2023-38545

This flaw makes curl overflow a heap based buffer in the SOCKS5 proxy handshake. When curl is asked to pass along the host name to the SOCKS5 proxy to allow that to resolve the address instead of it getting done by curl itself, the maximum length that host name can be is 255 bytes. If the host name is detected to be longer, curl switches to local name resolving and instead passes on the resolved address only. Due to this bug, the local variable that means "let the host resolve the name" could get the wrong value during a slow SOCKS5 handshake, and contrary to the intention, copy the too long host name to the target buffer instead of copying just the resolved address there. The target buffer being a heap based buffer, and the host name coming from the URL that curl has been told to operate with.

This flaw makes curl overflow a heap based buffer in the SOCKS5 proxy handshake. When curl is asked to pass along the host name to the SOCKS5 proxy to allow that to resolve the address instead of it getting done by curl itself, the maximum length that host name can be is 255 bytes. If the host name is detected to be longer, curl switches to local name resolving and instead passes on the resolved address only. Due to this bug, the local variable that means "let the host resolve the name" could get the wrong value during a slow SOCKS5 handshake, and contrary to the intention, copy the too long host name to the target buffer instead of copying just the resolved address there. The target buffer being a heap based buffer, and the host name coming from the URL that curl has been told to operate with.

Esta falla hace que curl desborde un búfer basado en el protocolo de enlace del proxy SOCKS5. Cuando se le pide a curl que pase el nombre de host al proxy SOCKS5 para permitir que resuelva la dirección en lugar de que lo haga curl mismo, la longitud máxima que puede tener el nombre de host es 255 bytes. Si se detecta que el nombre de host es más largo, curl cambia a la resolución de nombres local y en su lugar pasa solo la dirección resuelta. Debido a este error, la variable local que significa "dejar que el host resuelva el nombre" podría obtener el valor incorrecto durante un protocolo de enlace SOCKS5 lento y, contrariamente a la intención, copiar el nombre del host demasiado largo al búfer de destino en lugar de copiar solo la dirección resuelta allí. El búfer de destino es un búfer basado en montón y el nombre de host proviene de la URL con la que se le ha dicho a curl que opere.