CVE-2018-18586

Exp

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

Published: 2018-10-23 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2018-18586 is rated High Exploit Risk (69.3/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 3.28%). 1 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +2.68% over the last day, indicating growing attacker interest. Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2018-18586

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2018-18586

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.61% 3.28% +2.68%
2 2026-05-30 0.52% 0.61% +0.09%
3 2025-11-21 — 0.52% —

Full EPSS history (13 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-18586

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.0 MEDIUM
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 1.4 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2018-18586

OS Trackers for CVE-2018-18586

vendor priority summary link
alpine — CVE-2018-18586: 1 source package rows (libmspack); 9 state rows across 9 repos (3.10-main, 3.11-main, 3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 9, open 0. https://security.alpinelinux.org/vuln/CVE-2018-18586
debian unimportant CVE-2018-18586 unimportant priority: Debian including 1 source packages (libmspack), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2018-18586
gentoo normal CVE-2018-18586: 1 GLSA(s) (201903-20), 2 atom(s) (app-arch/cabextract, dev-libs/libmspack); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2018-18586
redhat medium — https://access.redhat.com/security/cve/CVE-2018-18586
ubuntu negligible CVE-2018-18586 negligible priority: Ubuntu including 2 source packages (clamav, libmspack), 10 status rows across 5 suites (bionic, cosmic, trusty, upstream, xenial): not-affected 8, needs-triage 2. https://ubuntu.com/security/CVE-2018-18586

Affected software / configurations for CVE-2018-18586

Vendor Product Version Raw CPE
kyzer libmspack 0.3 cpe:2.3:a:kyzer:libmspack:0.3:alpha:*:*:*:*:*:*
kyzer libmspack 0.4 cpe:2.3:a:kyzer:libmspack:0.4:alpha:*:*:*:*:*:*
kyzer libmspack 0.5 cpe:2.3:a:kyzer:libmspack:0.5:alpha:*:*:*:*:*:*
kyzer libmspack 0.6 cpe:2.3:a:kyzer:libmspack:0.6:alpha:*:*:*:*:*:*
kyzer libmspack 0.7 cpe:2.3:a:kyzer:libmspack:0.7:alpha:*:*:*:*:*:*

References for CVE-2018-18586

cvelogic Threat Intelligence