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High, CVSS 7.5amended

Moleculer: Unauthenticated Denial of Service via negative length field in the TCP transporter packet parser

CVE-2026-97705GHSA-h89v-g948-47vp

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (moleculer 0.15.2, 0.14.36), 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.

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Affected packages

  • npm moleculer

    Affected
    >= 0.15.0-beta1, < 0.15.2< 0.14.36
    Fixed in
    0.14.36, 0.15.2

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
  • CVE-2026-97705: 0.35% estimated exploitation activity in the next 30 days; percentile 28.95 (FIRST EPSS, 2026-11-10). 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 TCP transporter's packet parser (`src/transporters/tcp/parser.js`) reads the packet length field with `Buffer.prototype.readInt32BE`, a signed read. A crafted packet whose length field has the sign bit set yields a negative `length`. The parser then advances past the parsed message with `packet = packet.slice(length)`, but `Buffer.prototype.slice` clamps an out-of-range negative start index to `0`, so the buffer is returned unchanged. The `while (packet.length > 0)` loop condition therefore never becomes false, producing an infinite synchronous loop that blocks the Node.js event loop indefinitely.

Impact Any Moleculer node using the TCP transporter can be rendered completely unresponsive by an unauthenticated remote peer sending a single ~10-byte crafted TCP packet, before any protocol handshake or authentication takes place. `TcpReader.onTcpClientConnected` pipes each accepted socket's bytes straight into a fresh `Parser` instance (`socket.pipe(parser)`) with no…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 2 · amended ·

    Amended from osv record GHSA-h89v-g948-47vp

  2. Revision 1 · created ·

    Published from ghsa record GHSA-h89v-g948-47vp

Agent brief

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# Patch Next advisory brief: CVE-2026-97705

Advisory: Moleculer: Unauthenticated Denial of Service via negative length field in the TCP transporter packet parser
IDs: CVE-2026-97705, GHSA-h89v-g948-47vp
Record: https://patchnext.com/advisories/cve-2026-97705 (revision 2, source checked 10 Nov 2026, 06:25 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: moleculer 0.15.2, 0.14.36. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm moleculer: affected >= 0.15.0-beta1, < 0.15.2; < 0.14.36; fixed in 0.14.36, 0.15.2

## Suggested inspection (read-only)
- `npm ls moleculer --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 moleculer.
- 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://github.com/advisories/GHSA-h89v-g948-47vp (GitHub-reviewed advisory GHSA-h89v-g948-47vp lists affected ranges: npm moleculer >=0.15.0-beta1 =0 <0.14.36)
- Verified: https://osv.dev/vulnerability/GHSA-h89v-g948-47vp (OSV record GHSA-h89v-g948-47vp lists affected ranges: npm moleculer >=0.15.0-beta1 =0 <0.14.36 (fixed))

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