CVE-2026-11815 Overview
CVE-2026-11815 is an insecure deserialization vulnerability [CWE-502] affecting an API Gateway product disclosed by Broadcom. An attacker positioned between the client application and the API Gateway server can intercept and tamper with in-transit traffic to deliver crafted serialized payloads. When the server deserializes these manipulated objects, it can violate intended security boundaries or execute attacker-controlled code.
The issue requires a network-based man-in-the-middle (MITM) position and low privileges, but no user interaction. Successful exploitation may result in broken security expectations or remote code execution on the gateway host.
Critical Impact
Successful exploitation can lead to arbitrary object deserialization, potentially enabling remote code execution on the API Gateway server.
Affected Products
- Broadcom API Gateway (see vendor advisory for affected versions)
- Client applications communicating with the API Gateway server
- Deployments lacking end-to-end transport integrity controls
Discovery Timeline
- 2026-06-10 - CVE-2026-11815 published to the National Vulnerability Database (NVD)
- 2026-06-10 - Last updated in NVD database
Technical Details for CVE-2026-11815
Vulnerability Analysis
The vulnerability stems from the API Gateway accepting serialized object data from client traffic without sufficient integrity verification or type restriction during deserialization. An attacker who can intercept and modify the communication channel between the client and the gateway can substitute a legitimate serialized payload with a malicious one.
Deserialization of attacker-controlled objects allows the construction of unexpected object graphs. These graphs can invoke gadget chains during reconstruction, leading to logic that the application was not designed to execute. The result ranges from authorization bypass to arbitrary code execution in the gateway process context.
The advisory describes the impact as either broken security expectations or remote code execution, indicating that gadget availability in the deployed runtime determines the upper bound of impact.
Root Cause
The root cause is unsafe deserialization of objects received over the client-to-gateway channel without strict allow-listing of permitted types or cryptographic integrity controls. Trust is implicitly placed on the network path, which an MITM-capable attacker invalidates.
Attack Vector
Exploitation requires the attacker to occupy a network position that permits interception and modification of API Gateway traffic. This includes compromised network segments, hostile Wi-Fi, rogue proxies, or compromised intermediaries. The attacker replaces a legitimate serialized object in a request with a payload crafted against known gadget chains in the gateway runtime.
No verified public proof-of-concept is available. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. The Exploit Prediction Scoring System (EPSS) probability stands at 0.396%.
For technical specifics, refer to the Broadcom Security Advisory.
Detection Methods for CVE-2026-11815
Indicators of Compromise
- Unexpected child processes spawned by the API Gateway service account
- Outbound network connections from the gateway host to unfamiliar destinations following request processing
- Errors or stack traces in gateway logs referencing deserialization classes, readObject, or reflection-based instantiation
- Anomalous TLS termination or certificate warnings on the client-to-gateway path
Detection Strategies
- Inspect gateway request logs for serialized object markers such as rO0AB (Java) or aced0005 byte sequences in unexpected fields
- Monitor for process lineage anomalies where the gateway JVM or service binary launches shells, scripting engines, or download utilities
- Correlate authentication or authorization decisions with subsequent privileged actions to surface broken security expectations
Monitoring Recommendations
- Enable verbose audit logging on the API Gateway and forward events to a centralized log platform
- Baseline expected outbound connectivity from gateway hosts and alert on deviations
- Track changes to gateway configuration files, deployed policies, and runtime classpath
How to Mitigate CVE-2026-11815
Immediate Actions Required
- Apply vendor-supplied patches referenced in the Broadcom Security Advisory as soon as available
- Enforce mutually authenticated TLS (mTLS) between client applications and the API Gateway to defeat MITM tampering
- Restrict network paths to the API Gateway to trusted segments and identified clients only
- Rotate any credentials or tokens that traversed the affected channel if compromise is suspected
Patch Information
Consult the Broadcom Security Advisory for the fixed releases and upgrade guidance corresponding to your deployed API Gateway version. Schedule the update through your standard change management process and validate gateway functionality in a staging environment before production rollout.
Workarounds
- Terminate client traffic through a hardened reverse proxy that performs TLS pinning and rejects malformed payloads
- Disable or restrict deserialization endpoints not required for production workloads
- Implement allow-list-based deserialization filters at the runtime layer where supported (for example, JEP 290 filters for Java)
- Apply integrity controls such as signed payloads or message authentication codes on serialized objects exchanged with the gateway
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
