CVE-2026-24819
📋 TL;DR
This CVE describes an Improperly Controlled Sequential Memory Allocation vulnerability in the foxinmy weixin4j library, specifically in CharArrayBuffer.Java and ClassUtil.Java modules. Attackers could exploit this to cause memory exhaustion or potentially execute arbitrary code by manipulating memory allocation sequences. This affects any application using the vulnerable weixin4j library components.
💻 Affected Systems
- foxinmy weixin4j
⚠️ 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.
- 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 leading to complete system compromise, data exfiltration, or service disruption through memory exhaustion attacks.
Likely Case
Denial of service through memory exhaustion, causing application crashes or degraded performance.
If Mitigated
Limited impact with proper memory limits and input validation in place, potentially causing only minor performance issues.
🎯 Exploit Status
Exploitation requires understanding of Java memory management and ability to trigger specific allocation patterns
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version including pull request #229 changes
Vendor Advisory: https://github.com/foxinmy/weixin4j/pull/229
Restart Required: Yes
Instructions:
1. Update weixin4j library to version containing pull request #229 fixes. 2. Rebuild and redeploy affected applications. 3. Restart application services.
🔧 Temporary Workarounds
Implement memory limits
allConfigure JVM memory limits and monitoring to prevent memory exhaustion attacks
java -Xmx512m -Xms256m -XX:MaxMetaspaceSize=256m
Input validation and sanitization
allAdd strict input validation for data processed by vulnerable modules
🧯 If You Can't Patch
- Implement network segmentation to isolate affected systems
- Deploy WAF rules to detect and block suspicious memory allocation patterns
🔍 How to Verify
Check if Vulnerable:
Check if application uses weixin4j library and review dependencies for versions prior to pull request #229Check Version:
Check Maven/Gradle dependencies or examine weixin4j JAR file versionVerify Fix Applied:
Verify updated weixin4j version includes changes from pull request #229 and test memory allocation patterns📡 Detection & Monitoring
Log Indicators:
- Repeated OutOfMemoryError exceptions
- Unusual memory allocation patterns in JVM logs
- Application crashes with memory-related errors
Network Indicators:
- Unusually large payloads to endpoints using weixin4j
- Repeated connection attempts with varying data sizes
SIEM Query:
source="*jvm.log*" AND ("OutOfMemoryError" OR "java.lang.OutOfMemoryError")