vulnerability / NVI-00011943 / Revision 1
Socket.IO: Prototype Pollution via Unsafe Client Session Lookup
GitHub lists this reviewed advisory for @socket.io/cluster-engine. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
7.5 high
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
@socket.io/cluster-engine
source listed< 0.1.1
### Impact This is a **prototype pollution / improper client lookup** vulnerability in `@socket.io/cluster-engine`. Servers using `@socket.io/cluster-engine` may be impacted when attacker-controlled session IDs are processed in clustered deployments. A malicious client could use special property names such as `__proto__`, `constructor`, or other inherited object keys as a session identifier, causing the server to read properties from the object prototype chain instead of only real connected clients. The impact is **denial of service** through process crash. Applications not using `@socket.io/cluster-engine` are not affected by this specific issue. Affected versions: * `@socket.io/cluster-engine@0.1.0` ### Patches The issue was fixed in: * `@socket.io/cluster-engine@0.1.1` ### Workarounds If upgrading immediately is not possible, users can reduce exposure by: - Rejecting or sanitizing suspicious session IDs before they reach the cluster engine. - Running the cluster engine behind trusted infrastructure that prevents arbitrary clients from crafting raw Engine.IO session-related requests. These workarounds are defense-in-depth only. Upgrading to a patched version is rec
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-wfpm-5gcm-94cg ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.