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Fencer Vulns
medium 5.3

CVE-2025-15536 json

BYVoid OpenCC MaxMatchSegmentation.cpp MaxMatchSegmentation heap-based overflow

published 2026-01-18 9 mo ago modified 2026-06-17 4 mo ago also GHSA-5pr6-crvp-2j9f , EUVD-2026-3183

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 16%
public exploits
0
none known

Summary

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.

Patch / fix

  • npm opencc 1.2.0
  • opencc Debian 13 1.1.9+ds1-1+deb13u1
  • opencc Debian 14 1.1.9+ds1-4

debian advisories DEBIAN-CVE-2025-15536

  • opencc Ubuntu 22.04 LTS 1.1.3+ds1-3ubuntu3.1
  • opencc Ubuntu 24.04 LTS 1.1.7+ds1-1ubuntu0.1
  • opencc Ubuntu 25.10 1.1.9+ds1-2ubuntu0.1
  • opencc Ubuntu Pro 18.04 LTS 1.0.4-5ubuntu0.1~esm1
  • opencc Ubuntu Pro 20.04 LTS 1.0.5+git20190530-1ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2025-15536

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • opencc openSUSE Tumbleweed 1.2.0-1.1

opensuse advisories openSUSE-SU-2026:10102-1

  • opencc Alpine 3.24 1.2.0-r0

alpine advisories ALPINE-CVE-2025-15536

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-15536 updated cvss 5.3

opencc: OpenCC: Heap-based buffer overflow in MaxMatchSegmentation function allows local attackers to impact system integrity.

  • Red Hat Enterprise Linux 7 opencc, opencc-tools
    affected: no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
9 mo ago

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 16% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/BYVoid/OpenCC/issues/997 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/oneafter/1222/blob/main/repro referenced PoC, tagged "exploit" by a source, unverified
  • vuldb.com https://vuldb.com/?submit.733347 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 4.8 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
CNA 3.1 5.3 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
CNA 3.0 5.3 CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L/E:P/RL:O/RC:C
CNA 2.0 4.3 AV:L/AC:L/Au:S/C:P/I:P/A:P/E:POC/RL:OF/RC:C
CNA 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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CNA 3.1 5.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CNA 2.0 4.3 AV:L/AC:L/Au:S/C:P/I:P/A:P
GitHub 3.1 5.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

Affected packages

ecosystem package affected fixed in
npm opencc
<1.2.0
1.2.0

Affected products

  • BYVoid OpenCC

Classification

Weakness
  • CWE-122 Heap-based Buffer Overflow
  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
  • CWE-787 Out-of-bounds Write

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.