CyberRota Analysis
AI-GeneratedThe vulnerability arises from mcp-fetch's failure to properly handle bracketed IPv6 literals, allowing attackers to bypass security checks intended to prevent Server-Side Request Forgery (SSRF) attacks. This oversight can lead to unauthorized access to internal services and metadata endpoints, potentially exposing sensitive information. Organizations utilizing mcp-fetch should prioritize patching this vulnerability to mitigate the risk of exploitation, especially those with high-value internal systems or sensitive data.
Public Exploit Signal
A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.
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Original NVD Description
mcp-fetch checks a fetch target against its SSRF guard without removing the brackets that surround an IPv6 literal. isSafeUrl reads the hostname from the parsed URL, which for a literal such as http://[::1]/ yields the bracketed string, and then tests it with net.isIP. That call returns zero for a bracketed value, so the branch holding the private-address checks is skipped entirely. The guard falls back to resolving the hostname, the bracketed string is not a resolvable name, no addresses are returned, and the target is reported safe. The HTTP client then strips the brackets and connects. Because the address may be given in IPv4-mapped form, the same path reaches any IPv4 target the loopback and private checks were meant to exclude, including link-local metadata endpoints. isPrivateIPv6 also has no case for the ::ffff: prefix, so the mapped form would still pass even if the brackets were removed. The fetch target is supplied as a tool argument, so an attacker who can influence what the model requests can read internal responses back into the model context.