How severe is CVE-2019-1921?

CVE-2019-1921 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-2019-1921 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-1921?

CVE-2019-1921 affects Cisco Email Security Appliance. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2019-1921?

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

When was CVE-2019-1921 published?

CVE-2019-1921 was published on 2019-07-06 and last updated on 2026-06-17.

CVE-2019-1921

CVE-2019-1921 is a medium-severity vulnerability in Cisco Email Security Appliance 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: 1% (69th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Cisco Email Security Appliance
Published: 2019-07-06
Last modified: 2026-06-17

Description

A vulnerability in the attachment scanning of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to bypass configured content filters on the device. The vulnerability is due to improper input validation of the email body. An attacker could exploit this vulnerability by naming a malicious attachment with a specific pattern. A successful exploit could allow the attacker to bypass configured content filters that would normally block the attachment.

Frequently asked questions

What is CVE-2019-1921?: A vulnerability in the attachment scanning of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to bypass configured content filters on the device. The vulnerability is due to improper input validation of the email body. An attacker could exploit this vulnerability by naming a malicious attachment with a specific pattern. A successful exploit could allow the attacker to bypass configured content filters that would normally block the attachment.
How severe is CVE-2019-1921?: CVE-2019-1921 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-2019-1921 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-1921?: CVE-2019-1921 affects Cisco Email Security Appliance. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2019-1921?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2019-1921 published?: CVE-2019-1921 was published on 2019-07-06 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190703-esa-bypass

Affected products (1)

cpe:2.3:a:cisco:email_security_appliance:12.0.0-419:*:*:*:*:*:*:*

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