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GHSA/SYNC + updated 5 mcp gem advisories #1195
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,49 @@ | ||
| --- | ||
| gem: mcp | ||
| cve: 2026-67430 | ||
| ghsa: 52jp-gj8w-j6xh | ||
| url: https://nvd.nist.gov/vuln/detail/CVE-2026-67430 | ||
| title: Unbounded session retention in StreamableHTTPTransport allows | ||
| memory exhaustion via initialize flood | ||
| date: 2026-07-07 | ||
| description: | | ||
| ## Summary | ||
|
|
||
| In its default configuration, MCP::Server::Transports::StreamableHTTPTransport | ||
| never expires sessions. Every successful initialize request stores a | ||
| new ServerSession and a session record under a fresh UUID, and the | ||
| only path that removes them is an explicit client-issued HTTP DELETE. | ||
| An unauthenticated attacker can repeatedly initialize new sessions | ||
| and immediately disconnect, forcing the server to retain an unbounded | ||
| number of ServerSession objects until memory is exhausted. | ||
|
|
||
| ## Impact | ||
|
|
||
| - **Attacker requirements:** unauthenticated TCP reach of the MCP | ||
| endpoint. No session, no credentials. | ||
|
|
||
| - **Effect:** memory-exhaustion denial of service. A sustained or | ||
| distributed attacker can OOM the worker; on services that recycle | ||
| workers, the attacker simply repeats. On multi-tenant gateways, one | ||
| tenant can starve all others. | ||
|
|
||
| - **Affected deployments:** every deployment that does not opt into | ||
| `session_idle_timeout`. Because the README presents this as an | ||
| opt-in mitigation rather than a default, real-world deployments | ||
| are likely to ship vulnerable. | ||
| cvss_v3: 5.3 | ||
| patched_versions: | ||
| - ">= 0.23.0" | ||
| related: | ||
| url: | ||
| - https://nvd.nist.gov/vuln/detail/CVE-2026-67430 | ||
| - https://rubygems.org/gems/mcp/versions/0.23.0 | ||
| - https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.23.0 | ||
| - https://github.com/modelcontextprotocol/ruby-sdk/commit/afb968c468c178c4d3294b423fcce250621692f4 | ||
| - https://advisories.gitlab.com/gem/mcp/CVE-2026-67431 | ||
| - https://osv.dev/vulnerability/GHSA-52jp-gj8w-j6xh | ||
| - https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-52jp-gj8w-j6xh | ||
| - https://github.com/advisories/GHSA-52jp-gj8w-j6xh | ||
| notes: | | ||
| - cvss_v3 from GHSA | ||
| - date from gem release | ||
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,49 @@ | ||
| --- | ||
| gem: mcp | ||
| cve: 2026-67432 | ||
| ghsa: h669-8m4g-r2hc | ||
| url: https://nvd.nist.gov/vuln/detail/CVE-2026-67432 | ||
| title: Unbounded JSON-RPC request body causes uncontrolled memory | ||
| allocation in StreamableHTTPTransport | ||
| date: 2026-07-07 | ||
| description: | | ||
| ## Summary | ||
|
|
||
| An unauthenticated remote attacker can force any MCP Ruby SDK server | ||
| using MCP::Server::Transports::StreamableHTTPTransport to allocate | ||
| gigabytes of memory by sending a single oversized JSON-RPC POST. The | ||
| transport reads the entire HTTP body into a Ruby String and parses | ||
| it with JSON.parse(body, symbolize_names: true) with no size limit, | ||
| no Content-Length pre-check, and no streaming parser, allowing | ||
| trivial denial of service against the worker process. | ||
|
|
||
| ## Impact | ||
|
|
||
| - **Attacker requirements:** none beyond TCP reach of the MCP | ||
| endpoint. No session, no credentials, no prior interaction. | ||
|
|
||
| - **Effect:** memory-exhaustion denial of service. A single request | ||
| can take a worker offline; sustained low-rate requests keep the | ||
| service down across worker restarts. On multi-tenant deployments a | ||
| single attacker tenant can starve neighbours. | ||
|
|
||
| - **Affected deployments:** every server mounting | ||
| `MCP::Server::Transports::StreamableHTTPTransport` as a Rack | ||
| app — the canonical HTTP deployment pattern. Both stateful | ||
| and `stateless: true` configurations are affected. | ||
| cvss_v3: 7.5 | ||
| patched_versions: | ||
| - ">= 0.23.0" | ||
| related: | ||
| url: | ||
| - https://nvd.nist.gov/vuln/detail/CVE-2026-67432 | ||
| - https://rubygems.org/gems/mcp/versions/0.23.0 | ||
| - https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.23.0 | ||
| - https://github.com/modelcontextprotocol/ruby-sdk/commit/772e0cb1f9db69312006926eee59a7287ad50166 | ||
| - https://advisories.gitlab.com/gem/mcp/CVE-2026-67432 | ||
| - https://osv.dev/vulnerability/GHSA-h669-8m4g-r2hc | ||
| - https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-h669-8m4g-r2hc | ||
| - https://github.com/advisories/GHSA-h669-8m4g-r2hc | ||
| notes: | | ||
| - cvss_v3 from GHSA | ||
| - date from gem release |
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