How severe is CVE-2018-18586?

CVE-2018-18586 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2018-18586 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-18586?

CVE-2018-18586 primarily affects Kyzer Libmspack. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-18586?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2018-18586 published?

CVE-2018-18586 was published on 2018-10-23 and last updated on 2026-06-17.

CVE-2018-18586

CVE-2018-18586 is a medium-severity vulnerability in Kyzer Libmspack with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-22.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 5.0
EPSS exploit prediction: 3% (87th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-22
Affected product: Kyzer Libmspack
Published: 2018-10-23
Last modified: 2026-06-17

Description

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

Frequently asked questions

What is CVE-2018-18586?: 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
How severe is CVE-2018-18586?: CVE-2018-18586 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2018-18586 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-18586?: CVE-2018-18586 primarily affects Kyzer Libmspack. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-18586?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2018-18586 published?: CVE-2018-18586 was published on 2018-10-23 and last updated on 2026-06-17.

References

Affected products (5)

cpe:2.3:a:kyzer:libmspack:0.3:alpha:*:*:*:*:*:*
cpe:2.3:a:kyzer:libmspack:0.4:alpha:*:*:*:*:*:*
cpe:2.3:a:kyzer:libmspack:0.5:alpha:*:*:*:*:*:*
cpe:2.3:a:kyzer:libmspack:0.6:alpha:*:*:*:*:*:*
cpe:2.3:a:kyzer:libmspack:0.7:alpha:*:*:*:*:*:*

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