Fetching from the wire…
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Security2026-08-27 · source-backed
NVD published this against kazuph/mcp-fetch through 1.6.3 on August 26. isSafeUrl reads the hostname from the parsed URL, which for http://[::1]/ yields the bracketed string, then tests it with net.isIP, which returns zero for a bracketed value. The entire private-address branch is skipped, DNS resolution of the bracketed string returns nothing, and the target is declared safe before the HTTP client strips the brackets and connects (NVD). Because the address can be given in IPv4-mapped ::ffff: form, this reaches any IPv4 target the loopback checks existed to block, including cloud metadata endpoints. The fetch URL is a tool argument, so prompt injection is a sufficient trigger. Anyone writing an SSRF guard should test the bracketed form specifically.
Each link below shares sources, entities, or timing with this story.
Shared entities / Same source domain / Shared topic / Earlier coverage / Tension
Both cover August, CVE, DNS, NVD; reported by the same outlet (nvd.nist.gov); overlapping topics (against, august).
Shared entities
Both cover August, DNS, HTTP, IPv4.
Shared entities / Earlier coverage
Both cover August, CVE, CVSS, HTTP; earlier August coverage from 2026-08-07.
Shared entities / Same source domain / Earlier coverage
Both cover August, CVE, CVSS, NVD; reported by the same outlet (nvd.nist.gov); earlier August coverage from 2026-08-25.
Both cover August, CVE, CVSS, NVD; reported by the same outlet (nvd.nist.gov); earlier August coverage from 2026-08-23.
Shared entities / Earlier coverage / Tension
Both cover CVE, CVSS, DNS, HTTP; earlier CVE coverage from 2026-02-21; pushes against this story (but).
Shared entities / Shared topic / Earlier coverage / Tension
Both cover CVE, HTTP, SSRF; overlapping topics (against, return); earlier CVE coverage from 2026-07-23.
Shared entities / Same source domain / Shared topic
Both cover August, CVE, NVD; reported by the same outlet (nvd.nist.gov); overlapping topics (argument, august).