CVE-2025-15536
📋 TL;DR
A heap-based buffer overflow vulnerability exists in BYVoid OpenCC versions up to 1.1.9, specifically in the MaxMatchSegmentation function. This allows local attackers to execute arbitrary code or cause denial of service. Users of OpenCC for Chinese text conversion are affected.
💻 Affected Systems
- BYVoid OpenCC
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Local privilege escalation leading to full system compromise or persistent backdoor installation
Likely Case
Application crash (denial of service) or limited code execution in the context of the OpenCC process
If Mitigated
Minimal impact if proper sandboxing/containerization is used and OpenCC runs with minimal privileges
🎯 Exploit Status
Exploit code is publicly available on GitHub. Attack requires local access to execute OpenCC with malicious input.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after commit 345c9a50ab07018f1b4439776bad78a0d40778ec
Vendor Advisory: https://github.com/BYVoid/OpenCC/commit/345c9a50ab07018f1b4439776bad78a0d40778ec
Restart Required: No
Instructions:
1. Update OpenCC to latest version from official repository. 2. Recompile if using source. 3. Replace existing binary with patched version.
🔧 Temporary Workarounds
Restrict OpenCC execution
linuxLimit which users can execute OpenCC binary using file permissions or mandatory access controls
chmod 750 /usr/bin/opencc
setfacl -m u:trusteduser:rx /usr/bin/opencc
Run in sandboxed environment
allExecute OpenCC within container or sandbox with limited privileges
docker run --security-opt=no-new-privileges -v /path/to/data:/data opencc:latest
🧯 If You Can't Patch
- Remove or disable OpenCC binary from production systems
- Implement strict access controls to limit which users can execute OpenCC
🔍 How to Verify
Check if Vulnerable:
Check OpenCC version: opencc --version. If version is 1.1.9 or earlier, system is vulnerable.Check Version:
opencc --version 2>/dev/null || echo 'OpenCC not installed'Verify Fix Applied:
Verify commit hash contains 345c9a50ab07018f1b4439776bad78a0d40778ec or version is newer than 1.1.9📡 Detection & Monitoring
Log Indicators:
- Segmentation fault crashes of opencc process
- Abnormal memory usage patterns in OpenCC
Network Indicators:
- N/A (local exploit only)
SIEM Query:
process.name:"opencc" AND (event.action:"segmentation_fault" OR event.outcome:"failure")🔗 References
- https://github.com/BYVoid/OpenCC/
- https://github.com/BYVoid/OpenCC/commit/345c9a50ab07018f1b4439776bad78a0d40778ec
- https://github.com/BYVoid/OpenCC/issues/997
- https://github.com/BYVoid/OpenCC/pull/1005
- https://github.com/oneafter/1222/blob/main/repro
- https://vuldb.com/?ctiid.341708
- https://vuldb.com/?id.341708
- https://vuldb.com/?submit.733347
- https://github.com/BYVoid/OpenCC/issues/997
