Open Chinese Convert has Out-of-bounds Write

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

1.9 · CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P · score source

EPSS

• CVE-2025-15536: 0.25% estimated exploitation activity in the next 30 days; percentile 16.78 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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.

Published by the source

18 Jan 2026, 09:30 UTC

Last modified by the source

22 Feb 2026, 23:26 UTC

Source last checked

26 Oct 2026, 12:42 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-5pr6-crvp-2j9f

2. Revision 2 · amended · 24 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-5pr6-crvp-2j9f

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# Patch Next advisory brief: CVE-2025-15536

Advisory: Open Chinese Convert has Out-of-bounds Write
IDs: CVE-2025-15536, GHSA-5pr6-crvp-2j9f
Record: https://patchnext.com/advisories/cve-2025-15536 (revision 3, source checked 26 Oct 2026, 12:42 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 1.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: opencc 1.2.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm opencc: affected <= 1.1.9; fixed in 1.2.0

## Suggested inspection (read-only)
- `npm ls opencc --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on opencc.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-5pr6-crvp-2j9f (OSV record GHSA-5pr6-crvp-2j9f lists affected ranges: npm opencc >=0 <1.2.0 (fixed))
- Verified: https://github.com/advisories/GHSA-5pr6-crvp-2j9f (GitHub-reviewed advisory GHSA-5pr6-crvp-2j9f lists affected ranges: npm opencc >=0 <=1.1.9)

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