CVE-2026-33252

MEDIUMNVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 92% 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
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: None knownExposed: 0

A fix is available — apply it.

The Go MCP SDK used Go's standard encoding/json. Prior to version 1.4.1, the Go SDK's Streamable HTTP transport accepted browser-generated cross-site POST requests without validating the Origin header and without requiring Content-Type: application/json. In deployments without Authorization, especially stateless or sessionless configurations, this allows an arbitrary website to send MCP requests to a local server and potentially trigger tool execution. Version 1.4.1 contains a patch for the issue.

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: Track

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
Severity65% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
7%
KEV
Not listed

Published

March 24, 2026

Last Modified

June 17, 2026

Advisory Details (2)

Auto-updated Aug 4, 2026
Patch available. Sources: github_commit, github.
github Patch Available

Cross-Site Tool Execution for HTTP Servers without Authorization in github.com/modelcontextprotocol/go-sdk · Advisory · modelcontextprotocol/go-sdk · GitHub

https://github.com/modelcontextprotocol/go-sdk/security/advisories/GHSA-89xv-2j6f-qhc8
github_commit Patch Available

commit a433a831d6e5 (modelcontextprotocol/go-sdk)

Patch available: modelcontextprotocol/go-sdk v1.5.0-pre.1 (contains commit a433a831d6e5)

https://github.com/modelcontextprotocol/go-sdk/commit/a433a831d6e5d5ac3b9e625a8095aa8eaa040dfc

Vendor Advisories for CVE-2026-33252(1)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatdevspaces/udi-rhel9:17798297362026-05-28redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFixed inDependents
github.com/modelcontextprotocol/go-sdk—1.4.1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 41× 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.

Showing the most recent 100 of 166 total refreshes for this CVE.

  1. 2026-09-04 05:06 UTCEPSS rescore
  2. 2026-09-02 16:08 UTCOSV refresh
  3. 2026-09-02 14:11 UTCEPSS rescore
  4. 2026-09-01 13:53 UTCEPSS rescore
  5. 2026-09-01 04:39 UTCEPSS rescore
  6. 2026-09-01 04:39 UTCEPSS rescore
  7. 2026-08-30 19:17 UTCEPSS rescore
  8. 2026-08-30 01:22 UTCEPSS rescore
  9. 2026-08-28 21:41 UTCEPSS rescore
  10. 2026-08-27 14:25 UTCEPSS rescore
  11. 2026-08-26 14:46 UTCEPSS rescore
  12. 2026-08-24 14:17 UTCEPSS rescore
  13. 2026-08-21 23:49 UTCEPSS rescore
  14. 2026-08-20 22:55 UTCEPSS rescore
  15. 2026-08-20 22:55 UTCEPSS rescore
  16. 2026-08-19 17:03 UTCEPSS rescore
  17. 2026-08-18 13:48 UTCEPSS rescore
  18. 2026-08-17 13:47 UTCEPSS rescore
  19. 2026-08-16 14:56 UTCEPSS rescore
  20. 2026-08-16 10:43 UTCEG score recompute
  21. 2026-08-16 10:43 UTCVendor advisory
  22. 2026-08-16 02:14 UTCEPSS rescore
  23. 2026-08-15 01:30 UTCEPSS rescore
  24. 2026-08-14 06:55 UTCEG score recompute
  25. 2026-08-14 06:55 UTCVendor advisory
Show 75 more
  1. 2026-08-13 22:00 UTCEPSS rescore
  2. 2026-08-12 23:02 UTCEG score recompute
  3. 2026-08-12 23:02 UTCVendor advisory
  4. 2026-08-12 13:50 UTCEPSS rescore
  5. 2026-08-11 21:11 UTCEG score recompute
  6. 2026-08-11 21:11 UTCVendor advisory
  7. 2026-08-11 00:00 UTCEPSS rescore
  8. 2026-08-10 08:22 UTCEG score recompute
  9. 2026-08-10 08:22 UTCVendor advisory
  10. 2026-08-09 13:46 UTCEPSS rescore
  11. 2026-08-09 06:31 UTCEG score recompute
  12. 2026-08-09 06:31 UTCVendor advisory
  13. 2026-08-08 16:37 UTCEPSS rescore
  14. 2026-08-07 16:53 UTCEG score recompute
  15. 2026-08-07 16:53 UTCVendor advisory
  16. 2026-08-06 13:46 UTCEPSS rescore
  17. 2026-08-06 01:15 UTCEG score recompute
  18. 2026-08-06 01:15 UTCVendor advisory
  19. 2026-08-05 19:17 UTCEPSS rescore
  20. 2026-08-04 15:10 UTCEPSS rescore
  21. 2026-08-04 10:38 UTCEPSS rescore
  22. 2026-08-03 23:58 UTCEG score recompute
  23. 2026-08-03 23:58 UTCVendor advisory
  24. 2026-08-03 10:36 UTCEPSS rescore
  25. 2026-08-02 15:51 UTCEG score recompute▼ 0.60
  26. 2026-08-02 15:51 UTCVendor advisory
  27. 2026-08-02 02:27 UTCEPSS rescore
  28. 2026-08-01 04:16 UTCEPSS rescore
  29. 2026-07-30 16:28 UTCEPSS rescore
  30. 2026-07-30 01:30 UTCEPSS rescore
  31. 2026-07-27 14:13 UTCEPSS rescore
  32. 2026-07-26 14:54 UTCEPSS rescore
  33. 2026-07-26 14:54 UTCEPSS rescore
  34. 2026-07-25 14:18 UTCEPSS rescore
  35. 2026-07-25 14:18 UTCEPSS rescore
  36. 2026-07-24 14:17 UTCEPSS rescore
  37. 2026-07-24 14:17 UTCEPSS rescore
  38. 2026-07-23 14:18 UTCEPSS rescore
  39. 2026-07-23 14:18 UTCEPSS rescore
  40. 2026-07-23 03:09 UTCEG score recompute
  41. 2026-07-22 14:08 UTCEPSS rescore
  42. 2026-07-21 15:24 UTCEPSS rescore
  43. 2026-07-20 17:08 UTCEPSS rescore
  44. 2026-07-19 14:31 UTCEPSS rescore
  45. 2026-07-19 02:29 UTCEPSS rescore
  46. 2026-07-18 10:04 UTCEPSS rescore
  47. 2026-07-17 07:16 UTCOSV refresh
  48. 2026-07-16 17:03 UTCEPSS rescore
  49. 2026-07-15 16:57 UTCEPSS rescore
  50. 2026-07-15 16:57 UTCEPSS rescore
  51. 2026-07-15 02:00 UTCEPSS rescore
  52. 2026-07-15 02:00 UTCEPSS rescore
  53. 2026-07-13 22:30 UTCEPSS rescore
  54. 2026-07-13 06:13 UTCEPSS rescore
  55. 2026-07-13 06:13 UTCEPSS rescore
  56. 2026-07-12 05:46 UTCEPSS rescore
  57. 2026-07-11 08:27 UTCEPSS rescore
  58. 2026-07-09 19:10 UTCEPSS rescore
  59. 2026-07-08 15:15 UTCEPSS rescore
  60. 2026-07-07 13:46 UTCEPSS rescore
  61. 2026-07-06 16:27 UTCEPSS rescore
  62. 2026-07-06 16:27 UTCEPSS rescore
  63. 2026-07-06 02:23 UTCEPSS rescore
  64. 2026-07-06 02:23 UTCEPSS rescore
  65. 2026-07-05 02:30 UTCEPSS rescore
  66. 2026-07-04 06:31 UTCEPSS rescore
  67. 2026-07-01 15:06 UTCEPSS rescore
  68. 2026-06-30 23:22 UTCEPSS rescore
  69. 2026-06-29 14:06 UTCEPSS rescore
  70. 2026-06-29 14:06 UTCEPSS rescore
  71. 2026-06-29 05:32 UTCOSV refresh
  72. 2026-06-28 14:07 UTCEPSS rescore
  73. 2026-06-28 14:07 UTCEPSS rescore
  74. 2026-06-28 04:56 UTCEPSS rescore
  75. 2026-06-28 04:56 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-33252?
CVE-2026-33252 is a medium vulnerability published on March 24, 2026. The Go MCP SDK used Go's standard encoding/json. Prior to version 1.4.1, the Go SDK's Streamable HTTP transport accepted browser-generated cross-site POST requests without validating the Origin header and without requiring Content-Type: application/json. In deployments without Authorization,…
When was CVE-2026-33252 disclosed?
CVE-2026-33252 was first published in the National Vulnerability Database on March 24, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-33252 actively exploited?
CVE-2026-33252 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 92.6% of all scored CVEs.
What is the CVSS score of CVE-2026-33252?
CVE-2026-33252 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-33252?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-33252, 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.

Dependency Blast Radius

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