CVE-2026-92356: a2ui-project a2ui DOS Vulnerability

CVE-2026-92356 Overview

CVE-2026-92356 is a resource consumption vulnerability affecting a2ui-project a2ui versions 0.9 and 0.9.1. The flaw resides in the updateComponents function within the basic_functions.ts file, part of the Update Components module. Remote attackers with low privileges can trigger excessive resource usage by manipulating input to this function, leading to denial-of-service conditions. The weakness is classified under [CWE-400] (Uncontrolled Resource Consumption). The project maintainers were notified through a public issue report but had not responded at the time of disclosure. No official patch has been published.

Critical Impact
Remote attackers can exhaust application resources through repeated invocation of the vulnerable updateComponents function, degrading availability for legitimate users.

Affected Products

a2ui-project a2ui version 0.9
a2ui-project a2ui version 0.9.1
Component: Update Components (basic_functions.ts)

Discovery Timeline

2026-09-16 - CVE-2026-92356 published to NVD
2026-09-16 - Last updated in NVD database

Technical Details for CVE-2026-92356

Vulnerability Analysis

The vulnerability affects the updateComponents function in basic_functions.ts, which handles component update operations in the a2ui framework. Malicious input to this function causes uncontrolled resource consumption on the host processing the request. Because the attack vector is network-based and requires only low privileges with no user interaction, an authenticated attacker can trigger the condition remotely.

The issue is tracked under [CWE-400] (Uncontrolled Resource Consumption), a category covering flaws where an application fails to properly limit CPU, memory, or handles when processing attacker-controlled input. The a2ui-project maintainers were notified through GitHub Issue #2298 but had not acknowledged the report at time of disclosure.

Root Cause

The updateComponents function lacks adequate constraints on the input it processes. When invoked with crafted parameters, the function performs operations that consume disproportionate CPU or memory relative to the input size. Without input validation, iteration limits, or rate controls, repeated invocation escalates resource usage until service degradation occurs. Refer to the VulDB entry for CVE-2026-92356 for additional technical context.

Attack Vector

An attacker with valid low-privilege access to the a2ui application sends crafted requests that reach the updateComponents code path. Each request causes the server to allocate excessive resources. Repeated or concurrent requests amplify the effect, resulting in slow response times, thread exhaustion, or process termination. No user interaction is required, and the attack succeeds over the network. See the a2ui project repository for source-level context.

Detection Methods for CVE-2026-92356

Indicators of Compromise

Sustained CPU or memory spikes on hosts running a2ui 0.9 or 0.9.1 without corresponding legitimate workload.
Elevated request volume to endpoints that invoke the updateComponents function.
Application logs showing repeated component update operations from a single authenticated identity.
Timeouts, dropped connections, or process restarts affecting the a2ui service.

Detection Strategies

Baseline normal resource utilization for a2ui services and alert on statistical deviations.
Instrument the updateComponents code path with metrics on invocation frequency, execution time, and payload size.
Correlate authentication logs with resource utilization spikes to identify abusive low-privilege accounts.

Monitoring Recommendations

Monitor Node.js process memory, event loop lag, and CPU utilization on hosts running a2ui.
Track HTTP request rates and response latencies for endpoints that invoke component update logic.
Ingest application and web server logs into a centralized platform for anomaly analysis and long-term retention.

How to Mitigate CVE-2026-92356

Immediate Actions Required

Restrict network access to a2ui 0.9 and 0.9.1 deployments to trusted users until a patch is released.
Audit accounts with permission to invoke component update operations and revoke unnecessary access.
Deploy rate limiting in front of endpoints that reach the updateComponents function.
Monitor the a2ui GitHub repository and GitHub Issue #2298 for maintainer updates.

Patch Information

No official patch is available at the time of publication. The a2ui-project maintainers have not responded to the disclosure. Operators should track the project's issue tracker and release notes for future fixes and consider forking or applying local mitigations if the exposure is material to production workloads.

Workarounds

Place a reverse proxy in front of a2ui to enforce request size, rate, and concurrency limits on component update endpoints.
Apply resource quotas (cgroups, container CPU/memory limits) to contain the impact of a single misbehaving process.
Temporarily disable or gate the Update Components feature if it is not required for production operation.

bash

# Example: NGINX rate limiting for a2ui component update endpoint
http {
    limit_req_zone $binary_remote_addr zone=a2ui_update:10m rate=5r/m;

    server {
        location /api/components/update {
            limit_req zone=a2ui_update burst=10 nodelay;
            client_max_body_size 64k;
            proxy_pass http://a2ui_backend;
        }
    }
}