CVE-2026-10852 Overview
CVE-2026-10852 is a denial of service vulnerability in the WebSphere WebServer Plug-in component of IBM WebSphere Application Server and IBM WebSphere Application Server Liberty. An unauthenticated remote attacker can send crafted HTTP requests to the web server to trigger the condition. The flaw is classified under CWE-476: NULL Pointer Dereference, which causes the plug-in process to crash and disrupt service availability.
The vulnerability requires no privileges or user interaction, but the high attack complexity limits trivial mass exploitation. Successful exploitation impacts only availability — confidentiality and integrity are not affected.
Critical Impact
Remote unauthenticated attackers can crash the WebSphere WebServer Plug-in, interrupting service for applications hosted behind affected IBM WebSphere deployments.
Affected Products
- IBM WebSphere Application Server
- IBM WebSphere Application Server Liberty
- WebSphere WebServer Plug-in component
Discovery Timeline
- 2026-06-22 - CVE-2026-10852 published to NVD
- 2026-06-24 - Last updated in NVD database
Technical Details for CVE-2026-10852
Vulnerability Analysis
The vulnerability resides in the WebSphere WebServer Plug-in, the module that fronts IBM WebSphere Application Server and Liberty deployments by forwarding HTTP requests from a web server (such as IBM HTTP Server, Apache, or IIS) to the application server. The plug-in performs request parsing and routing logic before traffic reaches the application tier.
A crafted request triggers a NULL pointer dereference [CWE-476] within the plug-in's request processing path. When the dereference occurs, the worker process handling the request terminates abnormally. Repeated exploitation prevents the plug-in from servicing legitimate client traffic.
Exploitation requires only network access to the web server endpoint. No authentication, credentials, or user interaction are needed. The high attack complexity reflects the specific conditions or request structure required to reach the vulnerable code path reliably.
Root Cause
The defect is a missing NULL check in the WebSphere WebServer Plug-in. A specific input pattern produces a code path where a pointer is referenced without prior validation, causing a segmentation fault in the plug-in process.
Attack Vector
An attacker sends crafted HTTP requests across the network to a web server hosting the WebSphere Plug-in. The malformed input reaches the vulnerable parsing routine and triggers the dereference. Refer to the IBM Security Advisory for vendor technical details.
Detection Methods for CVE-2026-10852
Indicators of Compromise
- Unexpected termination or restart of WebSphere Plug-in worker processes within the front-end web server.
- Spikes in HTTP 500/502/503 responses returned to clients during otherwise normal traffic.
- Plug-in log entries showing abnormal segmentation faults or missing backend responses (http_plugin.log).
Detection Strategies
- Monitor web server error logs and the WebSphere Plug-in trace log for crash signatures and abrupt request termination.
- Correlate inbound request patterns with plug-in process restarts to identify malformed request bursts.
- Inspect HTTP traffic at the perimeter for anomalous header structures or oversized fields targeting WebSphere endpoints.
Monitoring Recommendations
- Track plug-in process uptime and restart frequency as a service health metric.
- Alert on sustained increases in 5xx error rates from WebSphere-fronted applications.
- Capture and retain request samples that precede plug-in crashes to support forensic analysis.
How to Mitigate CVE-2026-10852
Immediate Actions Required
- Review the IBM Security Advisory and apply the vendor-supplied interim fix or fix pack for affected WebSphere Application Server and Liberty versions.
- Inventory all systems running the WebSphere WebServer Plug-in and confirm version levels against IBM's remediation table.
- Restrict direct internet exposure of WebSphere-fronted web servers where feasible until patches are deployed.
Patch Information
IBM has published remediation guidance in IBM Support node 7277344. Apply the interim fix or upgrade to the fix pack version listed by IBM for both IBM WebSphere Application Server and IBM WebSphere Application Server Liberty. The plug-in binary itself must be updated on each web server host running the plug-in.
Workarounds
- Deploy a web application firewall (WAF) or reverse proxy in front of the WebSphere Plug-in to filter malformed requests.
- Enforce strict HTTP request validation, including limits on header size, header count, and unusual character sequences.
- Configure plug-in process supervision so crashed workers restart promptly to reduce service interruption windows.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
