Race condition in typescript-sdk - CVE-2026-25536
Published: November 9, 2026
Vulnerability identifier: #VU163208
CSH Severity: Low
CVSS v4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-25536
CWE-ID: CWE-362
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a low-privileged remote attacker to receive response data intended for other clients.
The vulnerability exists due to improper synchronization in the TypeScript SDK's StreamableHTTPServerTransport when a deployment reuses one transport instance for concurrent client requests with overlapping JSON-RPC message IDs. A low-privileged remote attacker can submit requests with matching message IDs while another client's requests are in flight, causing that client's responses to reach the attacker.
Affected software
typescript-sdk
How to mitigate CVE-2026-25536
Install security update from vendor's website.
typescript-sdk - update to 1.26.0