Vulnerability · Published Jan 18, 2026 · Assigned by VulDB
CVE-2025-15536BYVoid OpenCC MaxMatchSegmentation.cpp MaxMatchSegmentation heap-based overflow
Medium 5.3
In plain English
A medium-severity heap buffer overflow in OpenCC from BYVoid. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 17% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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 & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.24 | opencc | 1.2.0-r0 | ALPINE-CVE-2025-15536 |
| Debian:12 | opencc | no fix listed | DEBIAN-CVE-2025-15536 |
| Debian:13 | opencc | 1.1.9+ds1-1+deb13u1 | DEBIAN-CVE-2025-15536 |
| Debian:14 | opencc | 1.1.9+ds1-4 | DEBIAN-CVE-2025-15536 |
| Ubuntu:22.04:LTS | opencc | 1.1.3+ds1-3ubuntu3.1 | USN-7972-1 |
| Ubuntu:22.04:LTS | opencc | 1.1.3+ds1-3ubuntu3.1 | UBUNTU-CVE-2025-15536 |
| Ubuntu:24.04:LTS | opencc | 1.1.7+ds1-1ubuntu0.1 | USN-7972-1 |
| Ubuntu:24.04:LTS | opencc | 1.1.7+ds1-1ubuntu0.1 | UBUNTU-CVE-2025-15536 |
| Ubuntu:25.10 | opencc | 1.1.9+ds1-2ubuntu0.1 | USN-7972-1 |
| Ubuntu:25.10 | opencc | 1.1.9+ds1-2ubuntu0.1 | UBUNTU-CVE-2025-15536 |
| npm | opencc | 1.2.0 | GHSA-5pr6-crvp-2j9f |
Affected products (as reported)
Weakness: CWE-122, CWE-119 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L/E:P/RL:O/RC:C
References
- VDB-341708 | BYVoid OpenCC MaxMatchSegmentation.cpp MaxMatchSegmentation heap-based overflow vdb-entry, technical-description
- VDB-341708 | CTI Indicators (IOB, IOC, IOA) signature, permissions-required
- Submit #733347 | BYVoid OpenCC ver.1.1.9 and master-branch Heap-based Buffer Overflow third-party-advisory
- https://github.com/BYVoid/OpenCC/issues/997 issue-tracking
- https://github.com/BYVoid/OpenCC/pull/1005 issue-tracking
- https://github.com/oneafter/1222/blob/main/repro exploit
- https://github.com/BYVoid/OpenCC/commit/345c9a50ab07018f1b4439776bad78a0d40778ec patch
- https://github.com/BYVoid/OpenCC/ product