How severe is CVE-2018-6221?

CVE-2018-6221 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-6221 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-6221?

CVE-2018-6221 affects Trendmicro Email Encryption Gateway. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-6221?

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

When was CVE-2018-6221 published?

CVE-2018-6221 was published on 2018-03-15 and last updated on 2026-06-17.

CVE-2018-6221

CVE-2018-6221 is a high-severity vulnerability in Trendmicro Email Encryption Gateway with a CVSS 3.x base score of 8.1. 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-295.

Key facts

Severity: High (CVSS 3.x base score 8.1)
CVSS v2: 9.3
EPSS exploit prediction: 6% (93rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-295
Affected product: Trendmicro Email Encryption Gateway
Published: 2018-03-15
Last modified: 2026-06-17

Description

An unvalidated software update vulnerability in Trend Micro Email Encryption Gateway 5.5 could allow a man-in-the-middle attacker to tamper with an update file and inject their own.

Frequently asked questions

What is CVE-2018-6221?: An unvalidated software update vulnerability in Trend Micro Email Encryption Gateway 5.5 could allow a man-in-the-middle attacker to tamper with an update file and inject their own.
How severe is CVE-2018-6221?: CVE-2018-6221 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-6221 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-6221?: CVE-2018-6221 affects Trendmicro Email Encryption Gateway. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-6221?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2018-6221 published?: CVE-2018-6221 was published on 2018-03-15 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:trendmicro:email_encryption_gateway:5.5:*:*:*:*:*:*:*

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