CVE-2026-76893— tsParticles: A single anonymous MCP session can monopolize HTTP mode and deny new clients

Quick assessment

Affected

tsparticles tsparticles

Exploitation

No confirmed in-the-wild exploitation; assess based on exposure

Recommended action

Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

tsParticles 是一个用于创建高度可定制粒子动画的 TypeScript 库。在 4.3.2 版本之前，的 HTTP 模式会为所有客户端复用同一个有状态的。未认证的客户端若在首次发送初始化请求时未携带，便会抢占该共享传输状态，导致后续独立客户端收到"Server already initialized"（服务器已初始化）的错误，无法建立会话，直至进程重启。而首个客户端的会话仍可正常运行。该问题已在 4.3.2 版本中修复。

CVSS 6.9 · Medium Updated Nov 05, 2026

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service

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Vulnerability Information

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Vulnerability Title

tsParticles: A single anonymous MCP session can monopolize HTTP mode and deny new clients

Source: CVE Program / CVE List V5

Vulnerability 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.

Source: CVE Program / CVE List V5

CVSS Information

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

Source: CVE Program / CVE List V5

Vulnerability Type

未加控制的资源消耗(资源穷尽)

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
tsparticles	tsparticles	< 4.3.2	-
@tsparticles	mcp-server	< 4.3.2	-

II. Public POCs for CVE-2026-76893

#	POC Description	Source Link	Shenlong Link

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No public POC found.

III. Intelligence Information for CVE-2026-76893

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Other References for CVE-2026-76893 (3)

https://github.com/tsparticles/tsparticles/pull/5888 x_refsource_MISC
https://github.com/tsparticles/tsparticles/security/advisories/GHSA-h7c4-q426-7jh9 x_refsource_CONFIRM
https://github.com/tsparticles/tsparticles/commit/d3b5672bd61bb847abfa21193c34eabf7aba6896 x_refsource_MISC

https://www.cve.org/CVERecord?id=CVE-2026-76893

Same Patch Batch · tsparticles · 2026-11-04 · 4 CVEs total

CVE-2026-76892	8.7 HIGH	tsParticles: Malformed JSON requests can terminate the @tsparticles/mcp-server HTTP proces
CVE-2026-76826	7.5 HIGH	tsParticles: Generated release notes can execute shell commands in the stable publish work
CVE-2026-63655	7.5 HIGH	tsParticles: Unbounded HTTP Request Body Buffering in @tsparticles/mcp-server Leads to Rem

IV. Related Vulnerabilities

Same product: tsparticles

Same vendor: tsparticles

Same weakness: CWE-400