A Server-Side Request Forgery (SSRF) protection bypass existed in the html_to_markdown expansion module of misp-modules. The module attempts to prevent requests to loopback, private, link-local, and other restricted IP address ranges. However, IP addresses were compared against the blocked ranges without first normalising IPv4-mapped IPv6 addresses. An authenticated attacker able to invoke the module could supply an IPv4-mapped IPv6 address, such as: http://[::ffff:127.0.0.1]/ http://[::ffff:169.254.169.254]/ Alternatively, the attacker could use a hostname that resolves to an IPv4-mapped IPv6 address. These addresses were treated as IPv6 addresses and therefore did not match the corresponding blocked IPv4 ranges. Successful exploitation could cause the misp-modules server to connect to services available through its loopback interface, internal network, or link-local network. This could expose internal web services, administrative interfaces, or cloud instance metadata, with retr

A Server-Side Request Forgery (SSRF) protection bypass existed in the html_to_markdown expansion module of misp-modules. The module attempts to prevent requests to loopback, private, link-local, and other restricted IP address ranges. However, IP addresses were compared against the blocked ranges without first normalising IPv4-mapped IPv6 addresses. An authenticated attacker able to invoke the module could supply an IPv4-mapped IPv6 address, such as: http://[::ffff:127.0.0.1]/ http://[::ffff:169.254.169.254]/ Alternatively, the attacker could use a hostname that resolves to an IPv4-mapped IPv6 address. These addresses were treated as IPv6 addresses and therefore did not match the corresponding blocked IPv4 ranges. Successful exploitation could cause the misp-modules server to connect to services available through its loopback interface, internal network, or link-local network. This could expose internal web services, administrative interfaces, or cloud instance metadata, with r...