Skip to content
Patch Next
Sign inAdd to your agent

← Actionable
High, CVSS 8.7amended

MCP-Framework: Unbounded memory allocation in readRequestBody allows denial of service via HTTP transport

CVE-2026-39313GHSA-353c-v8x9-v7c3

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (mcp-framework 0.2.22), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

Add to your agent

Affected packages

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS 4.0
8.7 · 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 · score source
EPSS
  • CVE-2026-39313: 0.50% estimated exploitation activity in the next 30 days; percentile 42.52 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

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 A maxMessageSize configuration value exists in DEFAULTHTTPSTREAMCONFIG (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…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 3 · amended ·

    Amended from ghsa record GHSA-353c-v8x9-v7c3

  2. Revision 2 · amended ·

    Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

  3. Revision 1 · created ·

    Published from osv record GHSA-353c-v8x9-v7c3

Agent brief

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-39313

Advisory: MCP-Framework: Unbounded memory allocation in readRequestBody allows denial of service via HTTP transport
IDs: CVE-2026-39313, GHSA-353c-v8x9-v7c3
Record: https://patchnext.com/advisories/cve-2026-39313 (revision 3, source checked 26 Oct 2026, 12:48 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: mcp-framework 0.2.22. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm mcp-framework: affected <= 0.2.21; fixed in 0.2.22

## Suggested inspection (read-only)
- `npm ls mcp-framework --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on mcp-framework.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-353c-v8x9-v7c3 (OSV record GHSA-353c-v8x9-v7c3 lists affected ranges: npm mcp-framework >=0 <0.2.22 (fixed))
- Verified: https://github.com/advisories/GHSA-353c-v8x9-v7c3 (GitHub-reviewed advisory GHSA-353c-v8x9-v7c3 lists affected ranges: npm mcp-framework >=0 <=0.2.21)

Commands are suggestions: review each one before running it.

Loading voting…