CVE-2026-76893
tsParticles: A single anonymous MCP session can monopolize HTTP mode and deny new clients
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.
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| tsparticles tsparticles |
< 4.3.2 (affected) | CNA: GitHub_M |
| mcp-server @tsparticles |
< 4.3.2 (affected) | CNA: GitHub_M |
@tsparticles/mcp-server@tsparticles/mcp-server
npm |
<= 4.3.1 (affected, GitHub advisory range) | GitHub GHSA-h7c4-q426-7jh9 |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 6.9 medium |
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 | CNA: GitHub_M |
| 4.0 / 6.9 medium |
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD: [email protected] |
Exploit evidence
- https://github.com/tsparticles/tsparticles/security/advisories/GHSA-h7c4-q426-7jh9
exploit · ADP: CISA-ADP
References
- https://github.com/tsparticles/tsparticles/security/advisories/GHSA-h7c4-q426-7jh9CNA: GitHub_M · x_refsource_CONFIRM
- https://github.com/tsparticles/tsparticles/pull/5888CNA: GitHub_M · x_refsource_MISC
- https://github.com/tsparticles/tsparticles/commit/d3b5672bd61bb847abfa21193c34eabf7aba6896CNA: GitHub_M · x_refsource_MISC
- https://github.com/tsparticles/tsparticles/security/advisories/GHSA-h7c4-q426-7jh9ADP: CISA-ADP · exploit
- https://github.com/tsparticles/tsparticles/commit/d3b5672bd61bb847abfa21193c34eabf7aba6896[email protected]
- https://github.com/tsparticles/tsparticles/pull/5888[email protected]
- https://github.com/tsparticles/tsparticles/security/advisories/GHSA-h7c4-q426-7jh9[email protected]
- https://github.com/tsparticles/tsparticles/security/advisories/GHSA-h7c4-q426-7jh9134c704f-9b21-4f2e-91b3-4a467353bcc0
- https://github.com/tsparticles/tsparticles/security/advisories/GHSA-h7c4-q426-7jh9GitHub Security Advisories · advisory
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