What is CVE-2025-15536?

CVE-2025-15536 is a medium-severity vulnerability in Byvoid Opencc, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 5.3/10. Published 2026-01-18.

How severe is CVE-2025-15536?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Buffer overflow in Byvoid Opencc

CVE-2025-15536

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.

Vulnerability class: Buffer Overflow

Published 2026-01-18 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.003 (15.6th percentile), scored 2026-10-02.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 16th percentile — 15.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.000

Affected products

Byvoid Opencc — versions 1.1.0, 1.1.1, 1.1.2
Byvoid Open Chinese Convert

Weakness classification (CWE)

References

vuldb.com/ (technical-description, VDB Entry, Third Party Advisory, vdb-entry)
vuldb.com/ (signature, Permissions Required, permissions-required, VDB Entry)
vuldb.com/ (Exploit, VDB Entry, Third Party Advisory, third-party-advisory)
github.com/BYVoid/OpenCC/issues/997 (issue-tracking, Exploit, Patch, Issue Tracking)
github.com/BYVoid/OpenCC/pull/1005 (issue-tracking, Patch, Issue Tracking)
github.com/oneafter/1222/blob/main/repro (Product, exploit)
github.com/BYVoid/OpenCC/commit/345c9a50ab07018f1b4439776bad78a0d40778ec (Patch, patch)
github.com/BYVoid/OpenCC/ (product)

Frequently asked questions

What is CVE-2025-15536?: CVE-2025-15536 is a medium-severity vulnerability in Byvoid Opencc, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 5.3/10. Published 2026-01-18.
How severe is CVE-2025-15536?: Medium severity. CVSS v3 base score is 5.3 out of 10.