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Fencer Intel
medium 5.3

CVE-2018-18586 json

chmextract.c in the chmextract sample program, as distributed with libmspack before 0.8alpha, does not protect against absolute/relative pa…

published 8y ago modified 4mo ago also EUVD-2018-10306

cvss
5.3
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.3%
EPSS 3.3% chance of exploitation in 30 days, percentile 88%
public exploits
0
none known

Summary

chmextract.c in the chmextract sample program, as distributed with libmspack before 0.8alpha, does not protect against absolute/relative pathnames in CHM files, leading to Directory Traversal. NOTE: the vendor disputes that this is a libmspack vulnerability, because chmextract.c was only intended as a source-code example, not a supported application

Patch / fix

  • libmspack Debian 14, Debian 13, Debian 12 0.8-1

debian advisories DEBIAN-CVE-2018-18586

  • libmspack SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 0.4-15.13.1
  • libmspack SLE Real Time 15 SP2, SLE Module for Basesystem 15 SP3, SLE Micro 5.1 +1 more 0.6-3.14.1

suse advisories SUSE-SU-2022:4287-1SUSE-SU-2022:0069-2SUSE-SU-2022:0069-1

  • libmspack openSUSE Leap 15.3 0.6-3.14.1

opensuse advisories openSUSE-SU-2022:0069-1

  • libmspack Alpine 3.24, Alpine 3.23, Alpine 3.22 +16 more 0.8_alpha-r0

alpine advisories ALPINE-CVE-2018-18586

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

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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-2018-18586 updated cvss 5.3

libmspack: Directory traversal in chmextract.c

  • Red Hat Enterprise Linux 7 libmspack Red Hat Enterprise Linux 8 libmspack
    not affected: vulnerable code not present

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

Exploit prediction

3.28% chance of exploitation in the next 30 days, higher than 88% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/kyz/libmspack/commit/7cadd489698be117c47efcadd742651594429e6d referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 5.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Intel 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.