Baitaphish
Security intelligence
SearchLatest briefing
CVE Explorer

CVE-2026-33946

MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to version 0.9.2, the Ruby SDK's streamable_http_transport.rb implementation contains a session hijacking vulnerability. An attacker who obtains a valid session ID can completely hijack the victim's Server-Sent Events (SSE) stream and intercept all real-time data. Version 0.9.2 contains a patch.
Lifecycle PUBLISHED1 preserved revisionFact urn:baitaphish:canonical-cve-fact-revision:v2:de6934d5f57de9a5ecafd9f7a7e8b2743d80684d755bfddb7cec7f5452123011
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
1

Preserved source conflicts

No provider value was silently selected as the winner.

cwe · 2 assertions

{"cweId":"CWE-639","description":"CWE-639: Authorization Bypass Through User-Controlled Key","lang":"en","type":"CWE"}

  • cve_program_cvelist_v5cwe
    urn:baitaphish:normalized-source-record:v2:b18d079aae46e0a21cde08ae005440bb512251a1b7c50960e15296dcdc6ccf7c · sha256:a88d475a165622c1… · /containers/cna/problemTypes/1/descriptions/0

{"cweId":"CWE-384","description":"CWE-384: Session Fixation","lang":"en","type":"CWE"}

  • cve_program_cvelist_v5cwe
    urn:baitaphish:normalized-source-record:v2:b18d079aae46e0a21cde08ae005440bb512251a1b7c50960e15296dcdc6ccf7c · sha256:a88d475a165622c1… · /containers/cna/problemTypes/0/descriptions/0

Affected products and versions

1 source assertion
{"product":"ruby-sdk","vendor":"modelcontextprotocol","versions":[{"status":"affected","version":"< 0.9.2"}]}
  • cve_program_cvelist_v5affected
    urn:baitaphish:normalized-source-record:v2:b18d079aae46e0a21cde08ae005440bb512251a1b7c50960e15296dcdc6ccf7c · sha256:a88d475a165622c1… · /containers/cna/affected/0

Provider-owned CVSS observations

1 source assertion
{"metric":{"attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":8.2,"baseSeverity":"HIGH","privilegesRequired":"NONE","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"NONE"},"metric_type":"cvssV4_0"}
  • cve_program_cvelist_v5cvss
    urn:baitaphish:normalized-source-record:v2:b18d079aae46e0a21cde08ae005440bb512251a1b7c50960e15296dcdc6ccf7c · sha256:a88d475a165622c1… · /containers/cna/metrics/0/cvssV4_0

CWE assertions

2 source assertions
{"cweId":"CWE-639","description":"CWE-639: Authorization Bypass Through User-Controlled Key","lang":"en","type":"CWE"}
  • cve_program_cvelist_v5cwe
    urn:baitaphish:normalized-source-record:v2:b18d079aae46e0a21cde08ae005440bb512251a1b7c50960e15296dcdc6ccf7c · sha256:a88d475a165622c1… · /containers/cna/problemTypes/1/descriptions/0
{"cweId":"CWE-384","description":"CWE-384: Session Fixation","lang":"en","type":"CWE"}
  • cve_program_cvelist_v5cwe
    urn:baitaphish:normalized-source-record:v2:b18d079aae46e0a21cde08ae005440bb512251a1b7c50960e15296dcdc6ccf7c · sha256:a88d475a165622c1… · /containers/cna/problemTypes/0/descriptions/0

Source references

9 source assertions
{"name":"https://github.com/modelcontextprotocol/csharp-sdk/blob/main/src/ModelContextProtocol.AspNetCore/SseHandler.cs#L93-L97","tags":["x_refsource_MISC"],"url":"https://github.com/modelcontextprotocol/csharp-sdk/blob/main/src/ModelContextProtocol.AspNetCore/SseHandler.cs#L93-L97"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:b18d079aae46e0a21cde08ae005440bb512251a1b7c50960e15296dcdc6ccf7c · sha256:a88d475a165622c1… · /containers/cna/references/3
{"name":"https://github.com/modelcontextprotocol/go-sdk/blob/main/mcp/streamable.go#L281C1-L288C2","tags":["x_refsource_MISC"],"url":"https://github.com/modelcontextprotocol/go-sdk/blob/main/mcp/streamable.go#L281C1-L288C2"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:b18d079aae46e0a21cde08ae005440bb512251a1b7c50960e15296dcdc6ccf7c · sha256:a88d475a165622c1… · /containers/cna/references/4
{"name":"https://github.com/modelcontextprotocol/python-sdk/blob/main/src/mcp/server/streamable_http.py#L680-L685","tags":["x_refsource_MISC"],"url":"https://github.com/modelcontextprotocol/python-sdk/blob/main/src/mcp/server/streamable_http.py#L680-L685"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:b18d079aae46e0a21cde08ae005440bb512251a1b7c50960e15296dcdc6ccf7c · sha256:a88d475a165622c1… · /containers/cna/references/5
{"name":"https://github.com/modelcontextprotocol/ruby-sdk/blob/main/examples/streamable_http_server.rb","tags":["x_refsource_MISC"],"url":"https://github.com/modelcontextprotocol/ruby-sdk/blob/main/examples/streamable_http_server.rb"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:b18d079aae46e0a21cde08ae005440bb512251a1b7c50960e15296dcdc6ccf7c · sha256:a88d475a165622c1… · /containers/cna/references/6
{"name":"https://github.com/modelcontextprotocol/ruby-sdk/commit/db40143402d65b4fb6923cec42d2d72cb89b3874","tags":["x_refsource_MISC"],"url":"https://github.com/modelcontextprotocol/ruby-sdk/commit/db40143402d65b4fb6923cec42d2d72cb89b3874"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:b18d079aae46e0a21cde08ae005440bb512251a1b7c50960e15296dcdc6ccf7c · sha256:a88d475a165622c1… · /containers/cna/references/1
{"name":"https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.9.2","tags":["x_refsource_MISC"],"url":"https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.9.2"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:b18d079aae46e0a21cde08ae005440bb512251a1b7c50960e15296dcdc6ccf7c · sha256:a88d475a165622c1… · /containers/cna/references/7
{"tags":["exploit"],"url":"https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-qvqr-5cv7-wh35"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:b18d079aae46e0a21cde08ae005440bb512251a1b7c50960e15296dcdc6ccf7c · sha256:a88d475a165622c1… · /containers/adp/0/references/0
{"name":"https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-qvqr-5cv7-wh35","tags":["x_refsource_CONFIRM"],"url":"https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-qvqr-5cv7-wh35"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:b18d079aae46e0a21cde08ae005440bb512251a1b7c50960e15296dcdc6ccf7c · sha256:a88d475a165622c1… · /containers/cna/references/0
{"name":"https://hackerone.com/reports/3556146","tags":["x_refsource_MISC"],"url":"https://hackerone.com/reports/3556146"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:b18d079aae46e0a21cde08ae005440bb512251a1b7c50960e15296dcdc6ccf7c · sha256:a88d475a165622c1… · /containers/cna/references/2

Attribution and limitations

  • CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →

Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.

← Back to CVE Explorer