CVE-2026-67432

HIGHPre-NVD 7.57.5
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.8% (54th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
7.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.8%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem reads and parses an entire JSON-RPC POST body without a size limit, allowing an unauthenticated remote attacker to exhaust process memory. This issue is fixed in version 0.23.0.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
49
EG Risk 49/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed (value × EchelonGraph’s weight)
Severity75% × 45%
The EG Score, 7.5 of 10.
Exploitation0.8% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (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 at low or medium mission impact and sooner than that at high.
EPSS PROB
0.8%
EPSS %ILE
54th
KEV
Not listed

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

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (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)14 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (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

July 29, 2026

Last Modified

July 30, 2026

Advisory Details (3)

Auto-updated Jul 29, 2026
Patch available. Sources: github, github_commit, github_release.
GitHub release Patch Available

v0.23.0

Patch available: modelcontextprotocol/ruby-sdk v0.23.0

https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.23.0
GitHub commit Patch Available

commit 772e0cb1f9db (modelcontextprotocol/ruby-sdk)

Patch available: modelcontextprotocol/ruby-sdk v0.23.0 (contains commit 772e0cb1f9db)

https://github.com/modelcontextprotocol/ruby-sdk/commit/772e0cb1f9db69312006926eee59a7287ad50166
GitHub advisoryMentions a patch (unverified)

Unbounded JSON-RPC request body causes uncontrolled memory allocation in StreamableHTTPTransport · Advisory · modelcontextprotocol/ruby-sdk · GitHub

https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-h669-8m4g-r2hc

Vendor Advisories for CVE-2026-67432(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)
RubyGems(1)
PackageVulnerable rangeFix by version rangeDependents
mcp0.1.0 ... 0.9.2 (25 versions)
  • every version up to 0.23.0: fixed in 0.23.0
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 45× 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 100 of 128 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. None are among the latest 100 rows. The 28 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  2. 2026-10-13 10:23 UTCEG score recompute
  3. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.8% · 54th percentile
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  8. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  9. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  10. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  11. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.8% · 54th percentile
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  14. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.8% · 54th percentile
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  22. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  23. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  24. 2026-10-01 03:32 UTCEG score recompute
  25. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.8% · 54th percentile
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  1. 2026-09-29 07:32 UTCEG score recompute
  2. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  3. 2026-09-27 19:35 UTCEG score recompute
  4. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  5. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  6. 2026-09-25 05:31 UTCEG score recompute
  7. 2026-09-23 21:47 UTCEG score recompute
  8. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  9. 2026-09-23 03:09 UTCEG score recompute
  10. 2026-09-22 15:45 UTCEG score recompute
  11. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  12. 2026-09-20 00:21 UTCEG score recompute
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  14. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  15. 2026-09-18 01:39 UTCEG score recompute
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  17. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.4% · 36th percentile
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  24. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  25. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  26. 2026-09-10 19:48 UTCEG score recompute
  27. 2026-09-09 07:44 UTCEG score recompute
  28. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  29. 2026-09-07 20:36 UTCEG score recompute
  30. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.4% · 36th percentile
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  32. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.4% · 36th percentile
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  37. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.4% · 36th percentile
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  40. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.4% · 35th percentile
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  45. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  46. 2026-08-29 23:08 UTCEG score recompute
  47. 2026-08-28 21:42 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  48. 2026-08-27 22:33 UTCEG score recompute
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  50. 2026-08-26 14:47 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  51. 2026-08-26 00:51 UTCEG score recompute
  52. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  53. 2026-08-24 14:40 UTCEG score recompute
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  55. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  56. 2026-08-22 05:33 UTCEG score recompute
  57. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.4% · 36th percentile
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  59. 2026-08-20 22:56 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  60. 2026-08-19 20:33 UTCEG score recompute
  61. 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  62. 2026-08-18 21:45 UTCEG score recompute
  63. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.4% · 36th percentile
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  67. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  68. 2026-08-16 12:22 UTCEG score recompute
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  70. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  71. 2026-08-14 03:19 UTCEG score recompute
  72. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  73. 2026-08-12 17:09 UTCEG score recompute
  74. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  75. 2026-08-11 18:23 UTCEG score recompute

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-67432?
CVE-2026-67432 is a high-severity vulnerability; its CVE record was published on July 29, 2026. MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem reads and parses an entire JSON-RPC POST body without a size limit, allowing an unauthenticated remote attacker to exhaust process…
When was the CVE record for CVE-2026-67432 published?
The CVE record for CVE-2026-67432 was published on July 29, 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 July 30, 2026; the record at its source may have been updated since.
Is CVE-2026-67432 actively exploited?
CVE-2026-67432 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.8% probability of exploitation in the next 30 days (54th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-67432?
CVE-2026-67432 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-67432?
A fix for CVE-2026-67432 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-67432 are linked in the Vendor Advisories panel on this page.

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