CVE-2026-49252
deepstream is vulnerable to prototype pollution
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
deepstream is vulnerable to prototype pollution
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.
- Record
CVE-2026-49252- CVSS 3.1
- 9.9 Critical
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L - Weakness
- CWE-1321
- Updated
- 2026-11-02
EUVDEUVD-2026-37943
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.
- Record
EUVD-2026-37943- CVSS 3.1
- 9.9 Critical
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-9v98-6g37-x9g6
deepstream is vulnerable to prototype pollution
Impact
Prototype pollution in deepstream server v <=10.0.4. Potential privilege escalation from any authenticated user with write permission to any record.
Patches
Yes, upgrade to v10.0.5
Workarounds
Filter out all messages containing the path __proto__, constructor, prototype, before they reach the server's message pipeline
- Record
GHSA-9v98-6g37-x9g6- CVSS 3.1
- 9.9 Critical
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L - Weakness
- CWE-1321
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-49252- CVSS 3.1
- 9.9 Critical
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L - Weakness
- CWE-1321
- Updated
- 2026-11-02
OSV
deepstream is vulnerable to prototype pollution
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.
- Record
CVE-2026-49252- CVSS 3.1
- 9.9 Critical
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L - Weakness
- CWE-1321
- Updated
- 2026-11-02
OSVGHSA-9v98-6g37-x9g6
deepstream is vulnerable to prototype pollution
Impact
Prototype pollution in deepstream server v <=10.0.4. Potential privilege escalation from any authenticated user with write permission to any record.
Patches
Yes, upgrade to v10.0.5
Workarounds
Filter out all messages containing the path __proto__, constructor, prototype, before they reach the server's message pipeline
- Record
GHSA-9v98-6g37-x9g6- CVSS 3.1
- 9.9 Critical
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L - Weakness
- CWE-1321
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
@deepstream/servernpm |
before 10.0.5 | 10.0.5 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-49252 is a critical vulnerability (CVSS 9.9) in Deepstreamio Deepstream.io, published June 18, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.47%, the 40th percentile. Fixed in @deepstream/server 10.0.5.
References
github.com/deepstreamIO/deepstream.io/security/advisories/GHSA-9v98-6g37-x9g6
nvd.nist.gov/vuln/detail/CVE-2026-49252