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VulnerabilityPublished

CVE-2026-76892: Malformed JSON requests can terminate the @tsparticles/mcp-server HTTP process

Affects @tsparticles/mcp-serverSource GCVE Database

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Authoritative record:CVE-2026-76892· High 8.7

Not known to be exploited · CVSS 8.7 High : upgrade to 4.3.1 soon.

Data as of 9 Nov 2026, 23:24 UTC

CVSS 4.0 base score
8.7High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (GitHub_M)CVSS 4.08.7
EPSS
0.2% chance of exploitation in 30 days – higher than 21% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 4.3.1
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 4 Nov 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 9 Nov 2026.

What to do

Upgrade @tsparticles/mcp-server to 4.3.1.

Affected software

ProductAffectedFixed in
npm@tsparticles/mcp-serverAffected
  • <4.3.1
Fixed in
  • 4.3.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

## Summary The HTTP mode of `@tsparticles/mcp-server` parses incoming `/mcp` request bodies with `JSON.parse()` outside a request-local error boundary. A single malformed JSON request causes the async request handler to throw and terminates the Node.js process. This was verified on `v4.3.0` at commit `0266d469aa2d719cb66a9c6bf09aded4186ec17c`. Version `4.3.1` appears to fix this by returning HTTP 400 for invalid JSON. ## Affected Code The vulnerable handler is: if (req.method === "POST" && req.url === "/mcp") { const body = await new Promise<string>((resolve, reject) => { const chunks: Buffer[] = []; req.on("data", (chunk) => chunks.push(Buffer.from(chunk))); req.on("end", () => resolve(Buffer.concat(chunks).toString("utf8"))); req.on("error", reject); }); const parsedBody = body ? JSON.parse(body) : undefined; await transport.handleRequest(req, res, parsedBody); } The `JSON.parse()` call is not wrapped in `try/catch`. ## Reproduction Start the HTTP server and send this malformed request: POST /mcp HTTP/1.1 Content-Type: application/json Mcp-Protocol-Version: 2025-11-25 {"jsonrpc": Observed result in 3 out of 3 runs: exit_code=1 SyntaxError: Unexpected end of JSON input at Server.<anonymous> (integrations/mcp-server/src/index.ts:407:38) ## Impact An unauthenticated remote attacker can terminate the exposed MCP process with a single malformed request. The service remains unavailable until restarted by an external supervisor. ## Recommendation Wrap request parsing in a local `try/catch` and return a bounded HTTP 400 response such as: {"error":"Invalid JSON"} The process should remain alive after malformed requests.

References

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