CVE-2024-8176

What it actually does

A stack overflow vulnerability in libexpat caused by unbounded recursion during XML entity expansion, leading to stack exhaustion and potential crash or memory corruption.

Why it matters to the business

Applications using vulnerable libexpat versions for XML parsing can be crashed remotely, causing service disruption. Low exploitation likelihood based on current metrics and lack of KEV listing, but affects systems handling untrusted XML across the ecosystem.

How an attack unfolds

An attacker crafts an XML document with deeply nested entity references and sends it to a target application parsing XML with libexpat, triggering recursive expansion until stack overflow. No named threat actors or ransomware campaigns are associated with this issue.

How to fix it

Update libexpat to a version incorporating the fix from commit d068c3ff36fc6f4789988a09c69b434db757db53 in the Alpine aports repository. Apply patches or upgrade affected packages.

How to confirm the fix worked

Verify libexpat version is updated beyond the vulnerable commit. Test parsing of deeply nested entity XML without crash.

Typical attack path

1. Identify target application accepting XML input
2. Craft malicious XML with recursive entities
3. Transmit XML to parser
4. Trigger stack overflow leading to DoS or potential corruption

How to detect it

Look for application crashes during XML parsing in logs, unusual stack usage, or error messages related to entity expansion.

What your security team should do

• Prioritize patching libexpat in all XML-processing applications
• Monitor for updates in dependencies given 593 days since publication
• Implement input validation for XML depth if possible