tsParticles is a TypeScript library for creating highly customizable particle animations. Prior to 4.3.2, the HTTP mode of @tsparticles/mcp-server reuses one stateful StreamableHTTPServerTransport for every client. An unauthenticated client that sends the first initialize request without an mcp-session-id claims the shared transport state, causing later independent clients to receive Server already initialized and preventing them from establishing sessions until the process restarts. The first client's session remains functional. This issue is fixed in version 4.3.2.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact Low

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00291.

Exploitation poc

Automatable yes

Technical Impact partial

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
tsparticles tsparticles affected
Version Status Constraints
< 4.3.2 affected —
@tsparticles mcp-server affected
Version Status Constraints
< 4.3.2 affected —

No data.

No data.

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No data.

Project Subscriptions

No data.

Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/tsparticles/tsparticles/commit/d3b5672bd61bb847abfa21193c34eabf7aba6896 cve-icon cve-icon
https://github.com/tsparticles/tsparticles/pull/5888 cve-icon cve-icon
https://github.com/tsparticles/tsparticles/security/advisories/GHSA-h7c4-q426-7jh9 cve-icon cve-icon cve-icon
History

Fri, 06 Nov 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Wed, 04 Nov 2026 22:15:00 +0000

Type Values Removed Values Added
Description tsParticles is a TypeScript library for creating highly customizable particle animations. Prior to 4.3.2, the HTTP mode of @tsparticles/mcp-server reuses one stateful StreamableHTTPServerTransport for every client. An unauthenticated client that sends the first initialize request without an mcp-session-id claims the shared transport state, causing later independent clients to receive Server already initialized and preventing them from establishing sessions until the process restarts. The first client's session remains functional. This issue is fixed in version 4.3.2.
Title tsParticles: A single anonymous MCP session can monopolize HTTP mode and deny new clients
Weaknesses CWE-400
References
Metrics cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-11-05T20:20:55.808Z

Reserved: 2026-08-19T22:43:14.890Z

Link: CVE-2026-76893

cve-icon Vulnrichment

Updated: 2026-11-05T20:20:52.383Z

cve-icon NVD

Status : Received

Published: 2026-11-04T22:18:07.530

Modified: 2026-11-05T21:18:53.603

Link: CVE-2026-76893

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-11-05T00:15:15Z

Weaknesses