CVE-2026-49252 deepstream is vulnerable to prototype pollution
An authenticated user with write permissions can exploit prototype pollution to escalate privileges within the deepstream.io server.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-49252?
CVE-2026-49252 is a critical vulnerability in deepstreamIO deepstream.io, published on 18 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
deepstream is a server that allows clients and backend services to sync data, send messages and make rpcs at scale. Versions prior to 10.0.5 are vulnerable to Prototype Pollution. Exploitation can lead to potential privilege escalation from any authenticated user with write permission to any record. This issue has been fixed in version 10.0.5.
Weakness: CWE-1321
Which versions are affected by CVE-2026-49252?
2 open source packages ship an affected version, including @deepstream/server.
| Package | Affected | Fixed in |
|---|---|---|
@deepstream/server npm | All versions | 10.0.5 |
@deepstream/server npm | All versions | 10.0.5 |
How do I fix CVE-2026-49252?
Upgrade @deepstream/server to 10.0.5 or later.
Is CVE-2026-49252 being exploited?
There is no known exploitation of CVE-2026-49252 in the wild and no public exploit code.
Sources
Also known as GHSA-9v98-6g37-x9g6.