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Fencer Intel
high 7.1

CVE-2026-103980 json

ideon: SSRF protection bypass via IPv6 transition addresses (NAT64 / 6to4 / IPv4-mapped) in link preview

published 3mo ago modified 13h ago also GHSA-fwh7-rv72-xh5q , EUVD-2026-124033

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
7.1
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 0.9.6, the SSRF protection in safeFetch is bypassed by IPv6 transition addresses that embed private IPv4 addresses. The isPrivateIP function in src/app/lib/ssrf.ts checks only a narrow set of IPv6 ranges (loopback ::1, ULA fc/fd, link-local fe80) but does not recognize IPv4-mapped (::ffff:), NAT64 well-known (64:ff9b::/96, RFC 6052), NAT64 local-use (64:ff9b:1::/48, RFC 8215), 6to4 (2002::/16, RFC 3056), or Teredo (2001::/32, RFC 4380) encodings. An authenticated user can supply these addresses in link URLs to reach cloud metadata endpoints (169.254.169.254), localhost services, and RFC 1918 internal networks through the link preview metadata fetcher. This issue has been patched in version 0.9.6.

Patch / fix

Is CVE-2026-103980 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.

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CVSS scores

assigned by version score vector
CNA 4.0 7.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
CNA 4.0 7.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/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.