How severe is CVE-2016-6463?

CVE-2016-6463 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-2016-6463 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-6463?

CVE-2016-6463 primarily affects Cisco Email Security Appliance Firmware. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2016-6463?

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

When was CVE-2016-6463 published?

CVE-2016-6463 was published on 2016-11-19 and last updated on 2026-06-17.

CVE-2016-6463

CVE-2016-6463 is a medium-severity vulnerability in Cisco Email Security Appliance Firmware 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-20.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 5.0
EPSS exploit prediction: 1% (63rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Cisco Email Security Appliance Firmware
Published: 2016-11-19
Last modified: 2026-06-17

Description

A vulnerability in the email filtering functionality of Cisco AsyncOS Software for Cisco Email Security Appliances could allow an unauthenticated, remote attacker to bypass Advanced Malware Protection (AMP) filters that are configured for an affected device. This vulnerability affects all releases prior to the first fixed release of Cisco AsyncOS Software for both virtual and hardware versions of Cisco Email Security Appliances, if the AMP feature is configured to scan incoming email attachments. More Information: CSCuz85823. Known Affected Releases: 10.0.0-082 9.7.0-125 9.7.1-066. Known Fixed Releases: 10.0.0-203 9.7.2-131.

Frequently asked questions

What is CVE-2016-6463?: A vulnerability in the email filtering functionality of Cisco AsyncOS Software for Cisco Email Security Appliances could allow an unauthenticated, remote attacker to bypass Advanced Malware Protection (AMP) filters that are configured for an affected device. This vulnerability affects all releases prior to the first fixed release of Cisco AsyncOS Software for both virtual and hardware versions of Cisco Email Security Appliances, if the AMP feature is configured to scan incoming email attachments. More Information: CSCuz85823. Known Affected Releases: 10.0.0-082 9.7.0-125 9.7.1-066. Known Fixed Releases: 10.0.0-203 9.7.2-131.
How severe is CVE-2016-6463?: CVE-2016-6463 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-2016-6463 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-6463?: CVE-2016-6463 primarily affects Cisco Email Security Appliance Firmware. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2016-6463?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2016-6463 published?: CVE-2016-6463 was published on 2016-11-19 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:o:cisco:email_security_appliance_firmware:9.7.0-125:*:*:*:*:*:*:*
cpe:2.3:o:cisco:email_security_appliance_firmware:9.7.1-06:*:*:*:*:*:*:*
cpe:2.3:o:cisco:email_security_appliance_firmware:10.0.0-082:*:*:*:*:*:*:*

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