CVE-2026-25210
📋 TL;DR
This CVE describes an integer overflow vulnerability in libexpat's doContent function that can lead to buffer overflow during XML parsing. Attackers could exploit this to cause denial of service or potentially execute arbitrary code. Any application using vulnerable versions of libexpat for XML parsing is affected.
💻 Affected Systems
- libexpat
- Any software using libexpat for XML parsing
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise
Likely Case
Denial of service through application crash or memory corruption
If Mitigated
Application crash with no privilege escalation if proper sandboxing exists
🎯 Exploit Status
Exploitation requires crafting specific XML content to trigger the integer overflow
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.7.4
Vendor Advisory: https://github.com/libexpat/libexpat/pull/1075
Restart Required: Yes
Instructions:
1. Update libexpat to version 2.7.4 or later. 2. Recompile any applications statically linked to libexpat. 3. Restart affected services.
🔧 Temporary Workarounds
Disable XML parsing of untrusted content
allConfigure applications to avoid parsing XML from untrusted sources
Use system package manager update
linuxUpdate libexpat through your distribution's package manager
sudo apt update && sudo apt upgrade libexpat1
sudo yum update expat
🧯 If You Can't Patch
- Implement strict input validation for XML content
- Run applications with memory protection features like ASLR and DEP enabled
🔍 How to Verify
Check if Vulnerable:
Check libexpat version: expat --version or check package versionCheck Version:
expat --version 2>&1 | head -1Verify Fix Applied:
Verify libexpat version is 2.7.4 or higher📡 Detection & Monitoring
Log Indicators:
- Application crashes during XML parsing
- Memory corruption errors in application logs
Network Indicators:
- Unusually large or malformed XML payloads
SIEM Query:
source="application.log" AND ("segmentation fault" OR "memory corruption" OR "buffer overflow") AND "XML"