MCP TypeScript SDK: Missing session check for experimental tasks
Summary
The experimental tasks feature (taskStore) of the MCP TypeScript SDK does not check which session created a task. When several clients share one InMemoryTaskStore, a client can list, read and cancel the tasks of other clients. The attack needs only network access to the server and no authentication or user interaction.
Affected
- @modelcontextprotocol/sdk from 1.24.0 before 1.32.0 (vendor advisory: 1.24.0 through 1.31.x)
- Only servers or clients that use the experimental taskStore with InMemoryTaskStore are affected.
Fixed in
- Upgrade @modelcontextprotocol/sdk to 1.32.0 or later. A current 1.x release is preferred.
- The vendor states that 2.x packages are not affected.
Workaround
- Remove taskStore from the server configuration if experimental tasks are not needed.
- Alternatively, create one InMemoryTaskStore per session.
Exploitation
- CISA SSVC: exploitation none, automatable yes, technical impact partial.
- No reports of exploitation in the wild found. No CISA KEV listing. EPSS is low (0.00345).
- No public proof of concept found.
Our recommendation
- Inventory all @modelcontextprotocol/sdk versions in lockfiles, containers and MCP servers, including transitive dependencies.
- Upgrade affected installations to 1.32.0 or later.
- Search the code for taskStore. If it is used on a shared HTTP server, remove it or scope it per session.
- Check whether affected servers are reachable from the internet and serve more than one user or tenant.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- GitHub Security Advisory GHSA-22jm-h49p-29qw github.com
- Fix commit 727075b5 github.com
- Pull Request #2925 github.com
- Release 1.32.0 github.com
- OSV CVE-2026-111767 osv.dev
- GitLab Advisory CVE-2026-111767 advisories.gitlab.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 1 Nov 2026, 07:34.
Original description (NVD)
MCP TypeScript SDK is the official TypeScript SDK for Model Context Protocol servers and clients. From version 1.24.0 to before version 1.32.0, the experimental tasks feature (taskStore) did not check which session created a task. Clients sharing one InMemoryTaskStore could list, read and cancel each other's tasks. This issue has been patched in version 1.32.0.
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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