CVE-2026-25536@modelcontextprotocol/sdk has cross-client data leak via shared server/transport instance reuse
- 7.1HighCVSS base score
- 0.29%Exploitation in 30 daysEPSS · top 78% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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.
Timeline
ID reserved
By GitHub_M
- 2 days later
· 2 days later
Published
- 5 months later
· 5 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | High7.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N |
| redhat-SADPADP (enrichment) | 3.1 | High7.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N |
| NVDNVD · Modified | 3.1 | High7.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.29% · top 78% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.1.
Affected products
modelcontextprotocol · typescript-sdk
- affected >= 1.10.0, < 1.26.0
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- npm@modelcontextprotocol/sdkGHSA-345p-7cg4-v4c7 (opens in a new tab)
References
References7
- https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-345p-7cg4-v4c7 (opens in a new tab)x_refsource_CONFIRM
- https://github.com/modelcontextprotocol/typescript-sdk/issues/204 (opens in a new tab)x_refsource_MISC
- https://github.com/modelcontextprotocol/typescript-sdk/issues/243 (opens in a new tab)x_refsource_MISC
- https://access.redhat.com/security/cve/CVE-2026-25536 (opens in a new tab)vdb-entryx_refsource_REDHAT
- RHBZ#2436937 (opens in a new tab)issue-trackingx_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25536.json (opens in a new tab)x_sadp-csaf-vex
- https://access.redhat.com/errata/RHSA-2026:3960 (opens in a new tab)vendor-advisoryx_refsource_REDHAT
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-5335 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-345p-7cg4-v4c7 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-25536)Record last updated .