CVE-2026-31984: Audit Logging DoS Vulnerability

CVE-2026-31984 Overview

CVE-2026-31984 is a denial-of-service vulnerability in an audit logging component disclosed through a Nozomi Networks Security Advisory. The flaw stems from a missing size limit on input recorded into audit entries. An unauthenticated remote attacker can submit requests containing excessively large input that the audit subsystem writes to disk without bounds checking. Repeated or large requests can exhaust available disk space and render the system inoperable. The weakness is classified under CWE-770: Allocation of Resources Without Limits or Throttling.

Critical Impact
An unauthenticated network attacker can exhaust disk resources through oversized audit log entries, causing full availability loss of the affected system.

Affected Products

Specific affected product versions are not enumerated in the NVD record. Refer to the Nozomi Networks Security Advisory NN-2026:11-01 for the authoritative list of impacted products and fixed versions.

Discovery Timeline

2026-07-09 - CVE-2026-31984 published to NVD
2026-07-09 - Last updated in NVD database

Technical Details for CVE-2026-31984

Vulnerability Analysis

The vulnerability resides in the audit logging functionality of the affected product. Audit subsystems typically record request metadata, parameters, and payload fragments to persistent storage for compliance and forensic review. In this case, the logging routine records attacker-controlled input into audit entries without enforcing a maximum size on that input. Because the endpoint accepts unauthenticated requests, any network-reachable attacker can drive log growth at will. When the storage volume backing the audit log fills, dependent services fail to write state, accept new connections, or perform normal operations, producing a complete availability outage.

Root Cause

The root cause is a missing input length constraint in the code path that constructs audit records. The application trusts client-supplied fields and forwards them to the audit writer without truncation, sampling, or quota enforcement. This maps directly to CWE-770, where a resource — in this case disk capacity — is allocated proportionally to attacker-controlled input with no upper bound.

Attack Vector

Exploitation requires only network access to the vulnerable service. The attacker sends HTTP or protocol requests carrying oversized fields that the audit logger persists. No authentication, user interaction, or elevated privileges are required. Sustained requests amplify disk consumption until the filesystem is exhausted, at which point log rotation, database writes, and service processes may fail. See the vendor advisory for technical details of the vulnerable request paths.

Detection Methods for CVE-2026-31984

Indicators of Compromise

Rapid, unexplained growth of audit log files or the partition hosting them.
Repeated inbound requests from a single or small set of source IPs containing unusually large field values or payloads.
Service errors referencing "no space left on device," failed writes, or audit subsystem stalls.
Log entries whose recorded input size approaches or exceeds normal maximums for the application.

Detection Strategies

Baseline normal audit log growth rate and alert on statistical deviations over short intervals.
Inspect request bodies at the network or reverse-proxy layer for anomalously large parameters targeting endpoints known to be audited.
Correlate disk-utilization spikes on the log volume with inbound request volume from external sources.

Monitoring Recommendations

Monitor free disk space on partitions containing audit and application logs with low-threshold alerts.
Ingest audit log write metrics and web server access logs into a centralized platform to identify oversized-payload patterns.
Track process health for services that depend on the audit subsystem so downstream failures are surfaced quickly.

How to Mitigate CVE-2026-31984

Immediate Actions Required

Review the Nozomi Networks Security Advisory NN-2026:11-01 and apply the vendor-supplied fix as soon as it is available for your deployment.
Restrict network exposure of the affected service to trusted management networks until patched.
Provision additional disk capacity and confirm log rotation is functioning so a single burst cannot fill the volume.

Patch Information

Refer to the Nozomi Networks Security Advisory NN-2026:11-01 for fixed versions and upgrade instructions. Apply vendor patches through your standard change-management process and verify audit logging remains functional after the update.

Workarounds

Place a reverse proxy or web application firewall in front of the service and enforce strict maximum request and field sizes.
Rate-limit unauthenticated endpoints that feed the audit subsystem to reduce sustained log-growth potential.
Isolate audit log storage on a dedicated volume with quotas so exhaustion does not impact core service partitions.

bash

# Configuration example
# Refer to the Nozomi Networks advisory NN-2026:11-01 for vendor-specific configuration guidance.