How severe is CVE-2026-49252?

CVE-2026-49252 has a CVSS score of 9.9 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Which versions of @deepstream/server are affected by CVE-2026-49252?

@deepstream/server (npm) versions < 10.0.5 is affected.

Is there a fix for CVE-2026-49252?

Yes. CVE-2026-49252 is fixed in 10.0.5. Upgrade to this version or later.

Is CVE-2026-49252 exploitable, and should I be worried?

Whether CVE-2026-49252 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

What actually determines whether CVE-2026-49252 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

How do I fix CVE-2026-49252?

Upgrade @deepstream/server to 10.0.5 or later.

CVE-2026-49252 in @deepstream/server

Q: What is CVE-2026-49252?

CVE-2026-49252 is a critical-severity security vulnerability in @deepstream/server (npm), affecting versions < 10.0.5. It is fixed in 10.0.5.

Q: Is there a fix for CVE-2026-49252?

Yes. CVE-2026-49252 is fixed in 10.0.5. Upgrade to this version or later.

Q: Is CVE-2026-49252 exploitable, and should I be worried?

Whether CVE-2026-49252 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

Q: What actually determines whether CVE-2026-49252 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

Q: How do I fix CVE-2026-49252?

Upgrade @deepstream/server to 10.0.5 or later.

CVE-2026-49252

CVE-2026-49252 is a critical-severity security vulnerability in @deepstream/server (npm), affecting versions < 10.0.5. It is fixed in 10.0.5.

Check whether CVE-2026-49252 affects your applications

Kodem tells you whether this CVE is present, reachable, and actually executing in your application, so you know if it matters.

Thank you! Your submission has been received!

Oops! Something went wrong while submitting the form.

Runtime intelligence. Only the CVEs that actually run in production.

Summary

deepstream is vulnerable to prototype pollution

Workarounds

Filter out all messages containing the path __proto__, constructor, prototype, before they reach the server's message pipeline

Impact

Prototype pollution in deepstream server v <=10.0.4. Potential privilege escalation from any authenticated user with write permission to any record.

CVE-2026-49252 has a CVSS score of 9.9 (Critical). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (10.0.5); upgrading removes the vulnerable code path.

Affected versions

@deepstream/server (< 10.0.5)

Security releases

@deepstream/server → 10.0.5 (npm)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

Already deployed Kodem?

See it in your environment New to Kodem? Get a demo →

Remediation advice

Yes, upgrade to v10.0.5

Frequently Asked Questions

What is CVE-2026-49252? CVE-2026-49252 is a critical-severity security vulnerability in @deepstream/server (npm), affecting versions < 10.0.5. It is fixed in 10.0.5.
How severe is CVE-2026-49252? CVE-2026-49252 has a CVSS score of 9.9 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
Which versions of @deepstream/server are affected by CVE-2026-49252? @deepstream/server (npm) versions < 10.0.5 is affected.
Is there a fix for CVE-2026-49252? Yes. CVE-2026-49252 is fixed in 10.0.5. Upgrade to this version or later.
Is CVE-2026-49252 exploitable, and should I be worried? Whether CVE-2026-49252 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
What actually determines whether CVE-2026-49252 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
How do I fix CVE-2026-49252? Upgrade @deepstream/server to 10.0.5 or later.