How severe is CVE-2018-6823?

CVE-2018-6823 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-6823 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (71st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-6823?

CVE-2018-6823 affects Mailbutler Shimo. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-6823?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2018-6823 published?

CVE-2018-6823 was published on 2018-02-07 and last updated on 2026-06-17.

CVE-2018-6823

CVE-2018-6823 is a critical-severity vulnerability in Mailbutler Shimo with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 10.0
EPSS exploit prediction: 2% (71st percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Mailbutler Shimo
Published: 2018-02-07
Last modified: 2026-06-17

Description

In the VPN client in Mailbutler Shimo before 4.1.5.1 on macOS, the com.feingeist.shimo.helper tool LaunchDaemon implements an unprotected XPC service that can be abused to execute scripts as root.

Frequently asked questions

What is CVE-2018-6823?: In the VPN client in Mailbutler Shimo before 4.1.5.1 on macOS, the com.feingeist.shimo.helper tool LaunchDaemon implements an unprotected XPC service that can be abused to execute scripts as root.
How severe is CVE-2018-6823?: CVE-2018-6823 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-6823 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (71st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-6823?: CVE-2018-6823 affects Mailbutler Shimo. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-6823?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2018-6823 published?: CVE-2018-6823 was published on 2018-02-07 and last updated on 2026-06-17.

References

https://github.com/VerSprite/research/blob/master/advisories/VS-2018-001.md

Affected products (1)

cpe:2.3:a:mailbutler:shimo:*:*:*:*:*:macos:*:*

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