How severe is CVE-2017-3818?

CVE-2017-3818 has a CVSS 3.x base score of 5.8, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2017-3818 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-3818?

CVE-2017-3818 affects Cisco Email Security Appliance Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2017-3818?

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

When was CVE-2017-3818 published?

CVE-2017-3818 was published on 2017-02-03 and last updated on 2026-06-17.

CVE-2017-3818

CVE-2017-3818 is a medium-severity vulnerability in Cisco Email Security Appliance Firmware with a CVSS 3.x base score of 5.8. 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-20.

Key facts

Severity: Medium (CVSS 3.x base score 5.8)
CVSS v2: 5.0
EPSS exploit prediction: 2% (81st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Cisco Email Security Appliance Firmware
Published: 2017-02-03
Last modified: 2026-06-17

Description

A vulnerability in the Multipurpose Internet Mail Extensions (MIME) scanner of Cisco AsyncOS Software for Cisco Email Security Appliances (ESA) could allow an unauthenticated, remote attacker to bypass configured user filters on the device, aka a Malformed MIME Header Filtering Bypass. This vulnerability affects all releases prior to the first fixed release of Cisco AsyncOS Software for Cisco Email Security Appliances, both virtual and hardware appliances, if the software is configured to apply a message filter or content filter to incoming email attachments. More Information: CSCvb65245. Known Affected Releases: 9.7.1-066. Known Fixed Releases: 9.8.0-092.

Frequently asked questions

What is CVE-2017-3818?: A vulnerability in the Multipurpose Internet Mail Extensions (MIME) scanner of Cisco AsyncOS Software for Cisco Email Security Appliances (ESA) could allow an unauthenticated, remote attacker to bypass configured user filters on the device, aka a Malformed MIME Header Filtering Bypass. This vulnerability affects all releases prior to the first fixed release of Cisco AsyncOS Software for Cisco Email Security Appliances, both virtual and hardware appliances, if the software is configured to apply a message filter or content filter to incoming email attachments. More Information: CSCvb65245. Known Affected Releases: 9.7.1-066. Known Fixed Releases: 9.8.0-092.
How severe is CVE-2017-3818?: CVE-2017-3818 has a CVSS 3.x base score of 5.8, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2017-3818 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-3818?: CVE-2017-3818 affects Cisco Email Security Appliance Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2017-3818?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2017-3818 published?: CVE-2017-3818 was published on 2017-02-03 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:cisco:email_security_appliance_firmware:9.7.1-066:*:*:*:*:*:*:*

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