CVE-2026-39313: MCP-Framework Denial of Service Vulnerability

HIGH
Advisory Identifier: GHSA-353c-v8x9-v7c3
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CWE-770
Published
Advisory Summary

CVE-2026-39313 is a HIGH denial of service vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) affecting MCP-Framework libraries in the npm ecosystem. The issue involves unbounded memory allocation in readrequestbody allows denial of service via http transport. Remediation is available by upgrading affected packages to version 0.2.22.

CVE-2026-39313 at a Glance

CVE Identifier CVE-2026-39313
GHSA Identifier GHSA-353c-v8x9-v7c3
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-770: Allocation of Resources Without Limits or Throttling
Affected Product MCP-Framework
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2026-39313

To remediate this vulnerability, upgrade all affected MCP-Framework dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

mcp-framework fixed: 0.2.22 
npm install mcp-framework@0.2.22
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls mcp-framework

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-39313, inspect your project dependencies using npm:

npm ls mcp-framework

Analyze the terminal output to locate any version of MCP-Framework in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.2.22), your application is affected.

Note: The npm ls mcp-framework command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-770: Allocation of Resources Without Limits or Throttling, where the product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. In MCP-Framework, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary The `readRequestBody()` function in `src/transports/http/server.ts` concatenates HTTP request body chunks into a string with no size limit, allowing a remote unauthenticated attacker to crash the server via memory exhaustion with a single large HTTP POST request. ### Details **File:** `src/transports/http/server.ts`, lines 224-240 ```typescript private async readRequestBody(req: IncomingMessage): Promise<any> { return new Promise((resolve, reject) => { let body = ''; req.on('data', (chunk) => { body += chunk.toString(); // No size limit }); req.on('end', () => { try { const parsed = body ? JSON.parse(body) : null; resolve(parsed); } catch (error) { reject(error); } }); req.on('error', reject); }); } ``` A `maxMessageSize` configuration value exists in `DEFAULT_HTTP_STREAM_CONFIG` (4MB, defined in `src/transports/http/types.ts` line 124) but is never enforced in `readRequestBody()`. This creates a false sense of security. ### PoC Local testing with 50MB POST payloads against the vulnerable `readRequestBody()` function: | Trial | Payload | RSS growth | Time | Result | |-------|---------|-----------|------|--------| | 1 | 50MB | +197MB | 42ms | Vulnerable | | 2 | 50MB | +183MB | 46ms | Vulnerable | | 3 | 50MB | +15MB | 43ms | Vulnerable | | 4 | 50MB | +14MB | 32ms | Vulnerable | | 5 | 50MB | +65MB | 38ms | Vulnerable | Reproducibility: 5/5 (100%) ### Impact - **Denial of Service:** Any mcp-framework HTTP server can be crashed by a single large POST request to /mcp - **No authentication required:** readRequestBody() executes before any auth checks (auth is opt-in, default is no auth) - **Dead config:** maxMessageSize exists but is never enforced, giving a false sense of security - **Affected:** All applications using mcp-framework HttpStreamTransport (60,000 weekly npm downloads) **CWE-770:** Allocation of Resources Without Limits or Throttling **Suggested CVSS 3.1:** 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) ### Suggested Fix Enforce `maxMessageSize` in `readRequestBody()`: ```typescript private async readRequestBody(req: IncomingMessage): Promise<any> { const maxSize = this._config.maxMessageSize || 4 * 1024 * 1024; return new Promise((resolve, reject) => { let body = ''; let size = 0; req.on('data', (chunk) => { size += chunk.length; if (size > maxSize) { req.destroy(); reject(new Error('Request body too large')); return; } body += chunk.toString(); }); // ... }); } ``` ### Disclosure Timeline This report follows coordinated disclosure. I request a 90-day window before public disclosure. **Reporter:** Raza Sharif, CyberSecAI Ltd (contact@agentsign.dev)

CVE-2026-39313 Affected MCP-Framework Versions

1 component(s)
Fixed Versions:
0.2.22
Product / Package Ecosystem Affected Versions Fixed Version
mcp-framework
npm/mcp-framework
npm
< 0.2.22
0.2.22

References

GitHub Advisory / Wiki ADVISORY
https://github.com/QuantGeekDev/mcp-framework/security/advisories/GHSA-353c-v8x9-v7c3
NVD — CVE-2026-39313 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-39313
Security Fix Commit FIX COMMIT
https://github.com/QuantGeekDev/mcp-framework/commit/f97d2bb76d6359faf10cd1fc54b4911476b62524
MCP-Framework Source Repository REPOSITORY
https://github.com/QuantGeekDev/mcp-framework

Frequently Asked Questions

What is CVE-2026-39313?
CVE-2026-39313 is a security vulnerability in MCP-Framework involving Unbounded memory allocation in readRequestBody allows denial of service via HTTP transport under CWE-770: Allocation of Resources Without Limits or Throttling.
Which MCP-Framework versions are affected?
Affected versions include releases prior to 0.2.22 across affected packages: mcp-framework.
What version fixes CVE-2026-39313?
Upgrading to 0.2.22 (or the latest patched release for your respective branch) resolves the vulnerability.
Is mcp-framework affected?
Yes, mcp-framework is affected in releases prior to 0.2.22. Upgrade your dependency to 0.2.22 or later.
What CWE is associated with CVE-2026-39313?
CVE-2026-39313 is classified under CWE-770: Allocation of Resources Without Limits or Throttling (The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.).
How can I check npm dependencies for CVE-2026-39313?
Run the dependency tree command: 'npm ls mcp-framework'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-353c-v8x9-v7c3",
  "modified" : "2026-04-24T20:36:27Z",
  "published" : "2026-04-16T20:44:32Z",
  "aliases" : [ "CVE-2026-39313" ],
  "summary" : "MCP-Framework: Unbounded memory allocation in readRequestBody allows denial of service via HTTP transport",
  "details" : "### Summary\n\nThe `readRequestBody()` function in `src/transports/http/server.ts` concatenates HTTP request body chunks into a string with no size limit, allowing a remote unauthenticated attacker to crash the server via memory exhaustion with a single large HTTP POST request.\n\n### Details\n\n**File:** `src/transports/http/server.ts`, lines 224-240\n\n```typescript\nprivate async readRequestBody(req: IncomingMessage): Promise<any> {\n    return new Promise((resolve, reject) => {\n      let body = '';\n      req.on('data', (chunk) => {\n        body += chunk.toString();   // No size limit\n      });\n      req.on('end', () => {\n        try {\n          const parsed = body ? JSON.parse(body) : null;\n          resolve(parsed);\n        } catch (error) {\n          reject(error);\n        }\n      });\n      req.on('error', reject);\n    });\n  }\n```\n\nA `maxMessageSize` configuration value exists in `DEFAULT_HTTP_STREAM_CONFIG` (4MB, defined in `src/transports/http/types.ts` line 124) but is never enforced in `readRequestBody()`. This creates a false sense of security.\n\n### PoC\n\nLocal testing with 50MB POST payloads against the vulnerable `readRequestBody()` function:\n\n| Trial | Payload | RSS growth | Time | Result |\n|-------|---------|-----------|------|--------|\n| 1 | 50MB | +197MB | 42ms | Vulnerable |\n| 2 | 50MB | +183MB | 46ms | Vulnerable |\n| 3 | 50MB | +15MB | 43ms | Vulnerable |\n| 4 | 50MB | +14MB | 32ms | Vulnerable |\n| 5 | 50MB | +65MB | 38ms | Vulnerable |\n\nReproducibility: 5/5 (100%)\n\n### Impact\n\n- **Denial of Service:** Any mcp-framework HTTP server can be crashed by a single large POST request to /mcp\n- **No authentication required:** readRequestBody() executes before any auth checks (auth is opt-in, default is no auth)\n- **Dead config:** maxMessageSize exists but is never enforced, giving a false sense of security\n- **Affected:** All applications using mcp-framework HttpStreamTransport (60,000 weekly npm downloads)\n\n**CWE-770:** Allocation of Resources Without Limits or Throttling\n**Suggested CVSS 3.1:** 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)\n\n### Suggested Fix\n\nEnforce `maxMessageSize` in `readRequestBody()`:\n\n```typescript\nprivate async readRequestBody(req: IncomingMessage): Promise<any> {\n    const maxSize = this._config.maxMessageSize || 4 * 1024 * 1024;\n    return new Promise((resolve, reject) => {\n      let body = '';\n      let size = 0;\n      req.on('data', (chunk) => {\n        size += chunk.length;\n        if (size > maxSize) {\n          req.destroy();\n          reject(new Error('Request body too large'));\n          return;\n        }\n        body += chunk.toString();\n      });\n      // ...\n    });\n  }\n```\n\n### Disclosure Timeline\n\nThis report follows coordinated disclosure. I request a 90-day window before public disclosure.\n\n**Reporter:** Raza Sharif, CyberSecAI Ltd (contact@agentsign.dev)",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "mcp-framework"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.2.22"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.2.21"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/QuantGeekDev/mcp-framework/security/advisories/GHSA-353c-v8x9-v7c3"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-39313"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/QuantGeekDev/mcp-framework/commit/f97d2bb76d6359faf10cd1fc54b4911476b62524"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/QuantGeekDev/mcp-framework"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-770" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-16T20:44:32Z",
    "nvd_published_at" : "2026-04-16T22:16:38Z"
  }
}