Heap data disclosure via truncated UTF-8 input
Published Jan 18, 2026 · Updated Jan 18, 2026
Out-of-bounds reads in BYVoid OpenCC 1.1.0 through 1.1.9 allow local users to disclose heap data via truncated UTF-8 input. In MaxMatchSegmentation::Segment, NextCharLength can exceed the remaining byte count, so unsigned subtraction underflows and the next dictionary match reads beyond the heap buffer. Reachability requires a local user or embedding application to supply malformed conversion input; the over-read can expose adjacent heap bytes in output or terminate an instrumented process.
Summary
What happened
Out-of-bounds reads in BYVoid OpenCC 1.1.0 through 1.1.9 allow local users to disclose heap data via truncated UTF-8 input. In MaxMatchSegmentation::Segment, NextCharLength can exceed the remaining byte count, so unsigned subtraction underflows and the next dictionary match reads beyond the heap buffer. Reachability requires a local user or embedding application to supply malformed conversion input; the over-read can expose adjacent heap bytes in output or terminate an instrumented process.
The record
- CVE
- CVE-2025-15536
- Published
- Jan 18, 2026
- Updated
- Jan 18, 2026
- Vendor
- BYVoid
- Product
- OpenCC
- Classifications
- CWE-122, CWE-119
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jan 18, 2026CVE publishedPublication date reported by the CVE source.
- Jan 18, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=1.1.0
- Affected versionversion=1.1.1
- Affected versionversion=1.1.2
- Affected versionversion=1.1.3
- Affected versionversion=1.1.4
- Affected versionversion=1.1.5
- Affected versionversion=1.1.6
- Affected versionversion=1.1.7
- Affected versionversion=1.1.8
- Affected versionversion=1.1.9
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- OpenCC truncated UTF-8 reproducerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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