@modelcontextprotocol/sdk has cross-client data leak via shared server/transport instance reuse
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.1epss 0.3%
exploitation probability
0.3%top 80% of all CVEs
observed exploitation
nono source reports it
MCP TypeScript SDK is the official TypeScript SDK for Model Context Protocol servers and clients. From version 1.10.0 to 1.25.3, cross-client response data leak when a single McpServer/Server and transport instance is reused across multiple client connections, most commonly in stateless StreamableHTTPServerTransport deployments. This issue has been patched in version 1.26.0.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
Affected products
modelcontextprotocol · typescript-sdkReferences
https://access.redhat.com/errata/RHSA-2026:3960https://access.redhat.com/security/cve/CVE-2026-25536https://bugzilla.redhat.com/show_bug.cgi?id=2436937https://github.com/modelcontextprotocol/typescript-sdk/issues/204https://github.com/modelcontextprotocol/typescript-sdk/issues/243https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-345p-7cg4-v4c7https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25536.json