CVE-2025-15536 — opencc
Fix: BYVoid/OpenCC@345c9a5CVE-2025-15536 is a Buffer Overflow vulnerability in opencc. A fix is available for opencc — see the affected versions and patch details below.
BYVoid OpenCC MaxMatchSegmentation.cpp MaxMatchSegmentation heap-based overflow
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-15536.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
openccnpmDescription
A weakness has been identified in BYVoid OpenCC up to 1.1.9. This vulnerability affects the function opencc::MaxMatchSegmentation of the file src/MaxMatchSegmentation.cpp. This manipulation causes heap-based buffer overflow. The attack is restricted to local execution. The exploit has been made available to the public and could be used for attacks. Patch name: 345c9a50ab07018f1b4439776bad78a0d40778ec. To fix this issue, it is recommended to deploy a patch.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | opencc | all versions | 1.2.0npm install opencc@1.2.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for opencc, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update opencc to 1.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-15536 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-15536 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-15536. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-15536 in your dependencies?
O3 Security finds CVE-2025-15536 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.