CVE-2026-44430

MEDIUMNVD 4.04.0—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 4.0 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 80% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Elevated
4.0
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 4.0Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

The MCP Registry provides MCP clients with a list of MCP servers, like an app store for MCP servers. Prior to 1.7.7, the Registry's HTTP-based namespace verification (POST /v0/auth/http, POST /v0.1/auth/http) uses safeDialContext (internal/api/handlers/v0/auth/http.go:67-110) to refuse dialling private/internal addresses when fetching the well-known public-key file from a publisher-supplied domain. The blocklist (isBlockedIP, lines 125-133) relies entirely on Go stdlib's IsLoopback / IsPrivate / IsLinkLocalUnicast / IsMulticast / IsUnspecified plus a manual CGNAT range. None of these cover IPv6 6to4 (2002::/16), NAT64 (64:ff9b::/96 and 64:ff9b:1::/48 per RFC 8215), or deprecated site-local (fec0::/10) — all of which encode arbitrary IPv4 in the address bits and tunnel to RFC1918 / cloud-metadata services on dual-stack / NAT64-enabled hosts. This vulnerability is fixed in 1.7.7.

CVSS v3
4.0
EG Score
4.0(medium)
EPSS
20.4%
KEV
Not listed

Published

May 14, 2026

Last Modified

May 15, 2026

Advisory Details (1)

Auto-updated May 15, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

Unauthenticated SSRF: HTTP namespace verification dials 6to4 / NAT64 / site-local IPv6 addresses, bypassing private-address allowlist · Advisory · modelcontextprotocol/registry · GitHub

https://github.com/modelcontextprotocol/registry/security/advisories/GHSA-r48c-v28r-pf6v

Vendor Advisories for CVE-2026-44430(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFixed inDependents
github.com/modelcontextprotocol/registry—1.7.7—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 39× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-15 16:57 UTCEPSS rescore
  2. 2026-07-15 02:00 UTCEPSS rescore
  3. 2026-07-13 22:30 UTCEPSS rescore
  4. 2026-07-13 06:13 UTCEPSS rescore
  5. 2026-07-12 05:46 UTCEPSS rescore
  6. 2026-07-11 08:27 UTCEPSS rescore
  7. 2026-07-09 19:10 UTCEPSS rescore
  8. 2026-07-08 15:16 UTCEPSS rescore
  9. 2026-07-07 13:46 UTCEPSS rescore
  10. 2026-07-06 16:27 UTCEPSS rescore
  11. 2026-07-06 02:23 UTCEPSS rescore
  12. 2026-07-05 02:30 UTCEPSS rescore
  13. 2026-07-04 06:31 UTCEPSS rescore
  14. 2026-07-01 15:07 UTCEPSS rescore
  15. 2026-06-30 23:22 UTCEPSS rescore
  16. 2026-06-29 21:40 UTCEG score recompute
  17. 2026-06-29 14:06 UTCEPSS rescore
  18. 2026-06-28 14:07 UTCEPSS rescore
  19. 2026-06-28 04:56 UTCEPSS rescore
  20. 2026-06-27 23:01 UTCEG score recompute
  21. 2026-06-27 03:08 UTCEPSS rescore
  22. 2026-06-26 20:59 UTCEG score recompute
  23. 2026-06-25 18:59 UTCEG score recompute
  24. 2026-06-25 13:49 UTCEPSS rescore
  25. 2026-06-25 13:49 UTCEPSS rescore
Show 67 more
  1. 2026-06-24 14:05 UTCEPSS rescore
  2. 2026-06-23 21:33 UTCEPSS rescore
  3. 2026-06-22 14:25 UTCEPSS rescore
  4. 2026-06-22 14:25 UTCEPSS rescore
  5. 2026-06-21 14:56 UTCEPSS rescore
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  7. 2026-06-21 01:59 UTCEPSS rescore
  8. 2026-06-19 19:25 UTCEPSS rescore
  9. 2026-06-18 17:52 UTCEPSS rescore
  10. 2026-06-18 17:52 UTCEPSS rescore
  11. 2026-06-18 04:25 UTCEG score recompute
  12. 2026-06-17 17:53 UTCEPSS rescore
  13. 2026-06-17 01:46 UTCEG score recompute
  14. 2026-06-16 17:52 UTCEPSS rescore
  15. 2026-06-15 23:43 UTCEG score recompute
  16. 2026-06-15 17:49 UTCEPSS rescore
  17. 2026-06-14 06:23 UTCEG score recompute
  18. 2026-06-13 23:00 UTCEPSS rescore
  19. 2026-06-13 04:21 UTCEG score recompute
  20. 2026-06-12 23:12 UTCEPSS rescore
  21. 2026-06-12 23:12 UTCEPSS rescore
  22. 2026-06-12 01:51 UTCEG score recompute
  23. 2026-06-11 14:00 UTCEPSS rescore
  24. 2026-06-10 23:50 UTCEG score recompute
  25. 2026-06-10 22:18 UTCEPSS rescore
  26. 2026-06-10 13:22 UTCEPSS rescore
  27. 2026-06-10 13:22 UTCEPSS rescore
  28. 2026-06-09 21:50 UTCEG score recompute
  29. 2026-06-08 19:49 UTCEG score recompute
  30. 2026-06-08 14:17 UTCEPSS rescore
  31. 2026-06-08 14:17 UTCEPSS rescore
  32. 2026-06-07 17:45 UTCEG score recompute
  33. 2026-06-07 15:25 UTCEPSS rescore
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  35. 2026-06-06 15:44 UTCEG score recompute
  36. 2026-06-06 13:47 UTCEPSS rescore
  37. 2026-06-06 13:47 UTCEPSS rescore
  38. 2026-06-05 22:47 UTCEPSS rescore
  39. 2026-06-05 13:43 UTCEG score recompute
  40. 2026-06-05 06:10 UTCEPSS rescore
  41. 2026-06-05 06:10 UTCEPSS rescore
  42. 2026-06-04 13:12 UTCEPSS rescore
  43. 2026-06-04 13:12 UTCEPSS rescore
  44. 2026-06-04 11:42 UTCEG score recompute
  45. 2026-06-03 09:41 UTCEG score recompute
  46. 2026-06-02 20:13 UTCEPSS rescore
  47. 2026-06-02 07:40 UTCEG score recompute
  48. 2026-06-01 13:52 UTCEPSS rescore
  49. 2026-06-01 13:52 UTCEPSS rescore
  50. 2026-06-01 05:39 UTCEG score recompute
  51. 2026-05-31 22:30 UTCEPSS rescore
  52. 2026-05-31 22:30 UTCEPSS rescore
  53. 2026-05-31 00:16 UTCEPSS rescore
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  55. 2026-05-29 13:44 UTCEPSS rescore
  56. 2026-05-29 13:44 UTCEPSS rescore
  57. 2026-05-28 13:44 UTCEPSS rescore
  58. 2026-05-28 13:44 UTCEPSS rescore
  59. 2026-05-27 13:40 UTCEPSS rescore
  60. 2026-05-27 13:40 UTCEPSS rescore
  61. 2026-05-26 13:44 UTCEPSS rescore
  62. 2026-05-26 07:18 UTCEPSS rescore
  63. 2026-05-23 00:07 UTCEG score recompute
  64. 2026-05-21 22:43 UTCEPSS rescore
  65. 2026-05-20 22:38 UTCEPSS rescore
  66. 2026-05-20 12:08 UTCEG score recompute
  67. 2026-05-20 11:22 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-44430?
CVE-2026-44430 is a medium vulnerability published on May 14, 2026. The MCP Registry provides MCP clients with a list of MCP servers, like an app store for MCP servers. Prior to 1.7.7, the Registry's HTTP-based namespace verification (POST /v0/auth/http, POST /v0.1/auth/http) uses safeDialContext (internal/api/handlers/v0/auth/http.go:67-110) to refuse dialling…
When was CVE-2026-44430 disclosed?
CVE-2026-44430 was first published in the National Vulnerability Database on May 14, 2026, with the most recent update on May 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-44430 actively exploited?
CVE-2026-44430 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 20.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-44430?
CVE-2026-44430 has a CVSS v3 base score of 4.0 (NVD).
How do I remediate CVE-2026-44430?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-44430, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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