CVE-2024-8176 – A stack overflow vulnerability in libexpat allo... (How to Fix)

Q: What is the severity of CVE-2024-8176?

CVE-2024-8176 has a CVSS score of 7.5 (HIGH). A stack overflow vulnerability in libexpat allows attackers to cause denial of service or potentially memory corruption by sending XML documents with deeply nested entity references. This affects any software using vulnerable versions of libexpat for XML parsing. The vulnerability is triggered when parsing malicious XML input.

📋 TL;DR

A stack overflow vulnerability in libexpat allows attackers to cause denial of service or potentially memory corruption by sending XML documents with deeply nested entity references. This affects any software using vulnerable versions of libexpat for XML parsing. The vulnerability is triggered when parsing malicious XML input.

💻 Affected Systems

Products:

libexpat
software using libexpat for XML parsing

Versions: libexpat versions before 2.6.3

Operating Systems: Linux, Unix-like systems, Windows, macOS

Default Config Vulnerable: ⚠️ Yes

Notes: Any application using libexpat to parse untrusted XML input is vulnerable. This includes web servers, XML processors, and various system utilities.

⚠️ Manual Verification Required

This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.

Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).

🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.

Recommended Actions:

Review the CVE details at NVD
Check vendor security advisories for your specific version
Test if the vulnerability is exploitable in your environment
Consider updating to the latest version as a precaution

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution or complete system compromise if memory corruption leads to arbitrary code execution in privileged contexts.

🟠

Likely Case

Denial of service through application crashes when processing malicious XML input.

🟢

If Mitigated

Limited to application crashes with proper sandboxing and privilege separation.

🌐 Internet-Facing: HIGH

🏢 Internal Only: MEDIUM

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires sending specially crafted XML to a vulnerable parser. No authentication needed if the parser accepts external input.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: libexpat 2.6.3 or later

Vendor Advisory: https://access.redhat.com/errata/RHSA-2025:13681

Restart Required: Yes

Instructions:

1. Update libexpat to version 2.6.3 or later. 2. Restart affected services. 3. For Red Hat systems, use 'yum update expat' or 'dnf update expat'. 4. Rebuild any statically linked applications with the patched library.

🔧 Temporary Workarounds

Limit XML recursion depth

all

Configure XML parsers to limit entity expansion depth if supported by the application.

Input validation

all

Reject XML documents with excessive nesting or entity references before parsing.

🧯 If You Can't Patch

Implement network filtering to block XML input to vulnerable services
Isolate vulnerable systems in segmented network zones

🔍 How to Verify

Check if Vulnerable:

Check libexpat version: 'expat --version' or 'rpm -q expat' or 'dpkg -l libexpat1'

Check Version:

expat --version 2>&1 | head -1

Verify Fix Applied:

Verify version is 2.6.3 or later and test with sample XML containing nested entities

📡 Detection & Monitoring

Log Indicators:

Application crashes with stack overflow errors
XML parsing failures
Memory corruption warnings

Network Indicators:

Unusually large XML payloads
Multiple XML parsing requests from single source

SIEM Query:

source="application.log" AND ("stack overflow" OR "segmentation fault") AND process="*xml*"

📊 Metadata

CVE ID: CVE-2024-8176

CVSS v3 Score: 7.5 (HIGH)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CWE: CWE-674

EPSS Score: 0.42% exploit probability (61.2th percentile)

Published: March 14, 2025

Last Updated: December 9, 2025

🔗 References

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