Is this vulnerability remotely exploitable?

Yes. Because the affected functionality resides in the network-exposed gRPC server, a remote attacker who can reach the `sendMessage` endpoint may be able to exploit the unsafe deserialization behavior, subject to any authentication or network restrictions in place.

What level of access does an attacker need?

The attacker needs the ability to act as a gRPC client and send crafted messages to the server. In some deployments this may require valid client credentials or participation in the federated learning setup; in others, a publicly exposed endpoint may allow unauthenticated access.

What is the safest general fix pattern?

The most robust pattern is to eliminate unsafe deserialization of untrusted data altogether: rely on schema-based, data-only message formats; map messages to strongly typed, validated structures; and ensure no code execution or arbitrary object instantiation is possible during deserialization.

Severity:

HIGH RISK

(7.3)

Unsafe Message Deserialization (CWE-502) in FedML gRPC Server sendMessage

CVE-2026-5536

Published:

Apr 4, 2026

Status:

Analyzed

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

NDV

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Vulnerability Type

Category:

Unsafe Deserialization

CWE:

CWE-20;CWE-502

Impact:

Remote Code Execution and Data Compromise

Severity:

HIGH RISK

(7.3)

CVSS Version:

3.1

Vulnerability Type

Category:

Unsafe Deserialization

CWE:

CWE-20;CWE-502

Impact:

Remote Code Execution and Data Compromise

Severity:

HIGH RISK

(7.3)

CVSS Version:

3.1

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Unsafe Message Deserialization (CWE-502) in FedML gRPC Server sendMessage

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

Recent Vulnerabilities

HIGH RISK

HIGH

(8.8)

PHP Code Injection via File Upload (CWE-94) in Aero CMS Admin Post Creation

HIGH RISK

HIGH

(8.8)

Code Injection (CWE-94) via Module Parameters in Evolution CMS

Vulnerability Type

Vulnerability Type

Vulnerability Type

Catch This CVE While Code Is Being Written

Ship clean & secure code faster

Ship clean & secure code faster

Ship clean & secure code faster

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