CVE-2024-50602: Netapp Active IQ Unified Manager DoS Flaw

CVE-2024-50602 Overview

CVE-2024-50602 is a denial of service vulnerability discovered in libexpat, a widely-used XML parsing library. The vulnerability exists in versions prior to 2.6.4 and can cause application crashes when the XML_ResumeParser function is called after XML_StopParser has stopped or suspended an unstarted parser. This improper check for exceptional conditions (CWE-754) allows remote attackers to trigger denial of service conditions in applications that rely on libexpat for XML processing.

Critical Impact

Applications using vulnerable versions of libexpat may crash when processing specially crafted XML input, leading to service disruption across enterprise systems, storage infrastructure, and Linux distributions.

Affected Products

• libexpat_project libexpat (versions before 2.6.4)
• NetApp Active IQ Unified Manager
• NetApp SolidFire & HCI Management Node
• NetApp SolidFire & HCI Storage Node
• NetApp Windows Host Utilities
• NetApp HCI Compute Node
• NetApp H300S, H500S, H700S, H410S, H410C (and firmware)
• Debian Linux 11.0

Discovery Timeline

• October 27, 2024 - CVE-2024-50602 published to NVD
• October 15, 2025 - Last updated in NVD database

Technical Details for CVE-2024-50602

Vulnerability Analysis

This vulnerability stems from improper state management within libexpat's XML parser control functions. The core issue involves a logic flaw where XML_StopParser can be called to stop or suspend a parser that has not yet been properly initialized or started. When XML_ResumeParser is subsequently invoked to resume parsing operations, the function encounters an inconsistent internal state, leading to a crash.

The vulnerability is classified under CWE-754 (Improper Check for Unusual or Exceptional Conditions), indicating that the libexpat code fails to properly validate the parser's state before attempting to manipulate it. This represents a fundamental design oversight in the parser's state machine implementation.

Root Cause

The root cause lies in libexpat's insufficient validation of parser state transitions. The XML_StopParser function does not adequately check whether the parser has been properly started before allowing stop or suspend operations. When XML_ResumeParser attempts to continue parsing, it assumes the parser was in a valid stopped state from an active parsing session, but encounters undefined behavior when the parser was never properly initialized.

This improper exception handling means the library does not gracefully reject invalid state transitions, instead allowing operations that corrupt internal parser structures and ultimately cause application crashes.

Attack Vector

The attack vector for CVE-2024-50602 is network-based, allowing remote attackers to exploit this vulnerability without requiring authentication or user interaction. An attacker can exploit this vulnerability by:

1. Identifying applications that use libexpat for XML processing
2. Crafting input that triggers the vulnerable code path where XML_StopParser is called on an unstarted parser
3. Sending this malicious input to the target application
4. Causing the application to crash when XML_ResumeParser is called

While exploitation requires high attack complexity due to the specific conditions needed to trigger the vulnerability, successful exploitation results in complete availability impact, causing denial of service for affected applications and potentially disrupting critical infrastructure services.

The vulnerability mechanism involves the interaction between parser control functions. When an application calls XML_StopParser on a parser that hasn't started processing, the internal state becomes inconsistent. A subsequent call to XML_ResumeParser then fails catastrophically because it expects valid parsing context that doesn't exist. For technical details, see the GitHub Pull Request containing the fix.

Detection Methods for CVE-2024-50602

Indicators of Compromise

• Unexpected application crashes or segmentation faults in services using libexpat for XML parsing
• Core dumps containing stack traces pointing to XML_ResumeParser or related libexpat functions
• Service restarts or availability issues in applications dependent on XML processing
• Log entries indicating parser state errors or unhandled exceptions in XML processing modules

Detection Strategies

• Implement application crash monitoring to detect repeated failures in XML parsing services
• Deploy version scanning tools to identify systems running libexpat versions prior to 2.6.4
• Monitor system logs for segmentation faults or crash reports related to libexpat-dependent applications
• Use software composition analysis (SCA) tools to inventory libexpat usage across your environment

Monitoring Recommendations

• Configure crash reporting systems to alert on libexpat-related application failures
• Establish baseline availability metrics for XML-processing services to detect anomalies
• Implement health checks for critical applications using libexpat to quickly identify DoS conditions
• Review application dependencies regularly to ensure vulnerable library versions are identified

How to Mitigate CVE-2024-50602

Immediate Actions Required

• Upgrade libexpat to version 2.6.4 or later across all affected systems
• Inventory all applications and systems using libexpat, including NetApp storage infrastructure
• Prioritize patching for internet-facing services that process XML input
• Review and apply vendor-specific patches from NetApp and Debian as they become available

Patch Information

The vulnerability has been addressed in libexpat version 2.6.4. The fix ensures proper validation of parser state before allowing XML_StopParser and XML_ResumeParser operations. Organizations should apply updates according to their vendor's guidance:

• libexpat: Upgrade to version 2.6.4 or later. See the GitHub Pull Request for technical details on the fix.
• Debian Linux: Apply updates per the Debian LTS Announcement.
• NetApp Products: Review and apply patches per the NetApp Security Advisory.

Workarounds

• Implement input validation and rate limiting on services that accept XML input from untrusted sources
• Consider deploying web application firewalls (WAF) to filter potentially malicious XML requests
• Isolate XML processing services in containers or sandboxed environments to limit crash impact
• Implement automatic service restart policies to minimize downtime from potential exploitation

# Check installed libexpat version on Linux systems
dpkg -l | grep libexpat
rpm -qa | grep expat

# Verify library version programmatically
strings /usr/lib/libexpat.so* | grep -i "expat_"