Skip to content
Fencer Intel
medium 5.3

CVE-2026-65968 json

ideon: Unauthenticated SSRF in /api/proxy/image via WHATWG bracketed/hex-mapped IPv6 bypass of isSafeUrl guard

published 4mo ago modified 13h ago also GHSA-cvcr-fcf6-366r , EUVD-2026-124031

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository 3xpyth0n/ideon. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
5.3
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
—
no EPSS score yet
public exploits
0
none known

Summary

ideon is a self-hosted visual workspace. Prior to version 0.9.4, validateUrlForSSRF() / safeFetch() in lib/oauth/ssrf-protection.ts (and the parallel validateMcpUrl() in lib/security/validators.ts) perform SSRF host-blocking by string/regex matching on new URL(url).hostname. Their IPv6 branch only recognises the textual forms ::1, fe80:/fc00:/fd00: prefixes, and the dotted-decimal IPv4-mapped form ::ffff:127.x. It does not recognise the WHATWG-canonical IPv4-mapped-IPv6 host that Node emits for a mapped address, which is hex-compressed and bracket-wrapped: [::ffff:7f00:1] for 127.0.0.1, [::ffff:a9fe:a9fe] for 169.254.169.254. An authenticated user who registers a STREAMABLE_HTTP / SSE MCP server with URL http://[::ffff:7f00:1]:PORT/ (loopback) or http://[::ffff:a9fe:a9fe]/ (cloud metadata) passes both guards, and the server-side OAuth-discovery action then fetches that host, yielding server-side request forgery to loopback and to the cloud metadata service. This issue has been patched in version 0.9.4.

Patch / fix

Is CVE-2026-65968 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

CVSS scores

assigned by version score vector
CNA 4.0 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
CNA 4.0 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • 3xpyth0n ideon

Classification

Weakness
  • CWE-918 Server-Side Request Forgery

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of 3xpyth0n/ideon published their own advisory on GitHub. Reviewed sources take precedence over it.