CVE-2026-44430

MEDIUMNVD 4.04.0
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

This medium-severity CVE scores 4.0 under NVD CVSS v3. EPSS exploit probability: 0.3% (19th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, NVD CVSS v3
Elevated
4.0EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 4.0Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

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
4.0MEDIUMmedium confidence
EG Risk
34
EG Risk 34/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity40% × 45%
Impact severity (EG Severity): CVSS 4.0 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
19th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (4.0): severity, escalated by confirmed exploitation. This CVE's 4.0 is its impact severity (EG Severity), not escalated.

EG Severity
4.0 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-17). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

May 14, 2026

Last Modified

May 15, 2026

Advisory Details (1)

Auto-updated May 15, 2026
Patch available. Sources: github.
GitHub advisoryMentions a patch (unverified)

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 rangeFix by version rangeDependents
github.com/modelcontextprotocol/registry—
  • every version up to 1.7.7: fixed in 1.7.7
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 30× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 99 of 176 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 1 repeat row among the latest 100 is merged into the row it repeats. The 77 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  2. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  3. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  4. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  5. 2026-10-18 03:39 UTCEG score recompute
  6. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  7. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  8. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  9. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  10. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  11. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  12. 2026-10-12 16:05 UTCEG score recompute
  13. 2026-10-11 19:47 UTCEG score recompute
  14. 2026-10-11 17:01 UTCEG score recompute
  15. 2026-10-11 14:27 UTCEG score recompute
  16. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  17. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  18. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  19. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  20. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  21. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  22. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  23. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  24. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  25. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.3% · 19th percentile
Show 74 more
  1. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  2. 2026-09-30 04:58 UTCOSV refresh
  3. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  4. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  5. 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  6. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  7. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  8. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  9. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  10. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  11. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  12. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  13. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  14. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  15. 2026-09-11 07:53 UTCOSV refresh
  16. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  17. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  18. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  19. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  20. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  21. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  22. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  23. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  24. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  25. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  26. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  27. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  28. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  29. 2026-08-23 17:34 UTCEG score recompute
  30. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  31. 2026-08-22 01:37 UTCEG score recompute
  32. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  33. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  34. 2026-08-20 19:29 UTCEG score recompute
  35. 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  36. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  37. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  38. 2026-08-17 10:19 UTCEG score recompute
  39. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  40. 2026-08-16 03:52 UTCEG score recompute
  41. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  42. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  43. 2026-08-14 02:21 UTCEG score recompute
  44. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  45. 2026-08-12 14:56 UTCEG score recompute
  46. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  47. 2026-08-11 13:43 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  48. 2026-08-11 09:20 UTCEG score recompute
  49. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  50. 2026-08-10 07:19 UTCEG score recompute
  51. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  52. 2026-08-09 05:19 UTCEG score recompute
  53. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  54. 2026-08-08 03:19 UTCEG score recompute
  55. 2026-08-07 01:19 UTCEG score recompute
  56. 2026-08-06 13:46 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  57. 2026-08-05 21:33 UTCEG score recompute
  58. 2026-08-05 19:17 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  59. 2026-08-04 15:10 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  60. 2026-08-04 10:38 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  61. 2026-08-02 21:06 UTCEG score recompute
  62. 2026-08-02 02:27 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  63. 2026-08-01 19:05 UTCEG score recompute
  64. 2026-08-01 04:16 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  65. 2026-07-30 16:28 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  66. 2026-07-30 01:30 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  67. 2026-07-28 15:36 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  68. 2026-07-27 14:13 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  69. 2026-07-26 14:54 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  70. 2026-07-25 14:18 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  71. 2026-07-24 14:17 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  72. 2026-07-23 14:18 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  73. 2026-07-23 03:15 UTCEG score recompute
  74. 2026-07-22 14:08 UTCEPSS rescoreEPSS 0.3% · 20th percentile

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-44430?
CVE-2026-44430 is a medium-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-44430 published?
The CVE record for CVE-2026-44430 was published on May 14, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of May 15, 2026; the record at its source may have been updated since.
Is CVE-2026-44430 actively exploited?
CVE-2026-44430 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (19th percentile of EPSS-scored CVEs).
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?
A fix for CVE-2026-44430 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-44430 are linked in the Vendor Advisories panel on this page.

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