CVE-2019-1921
Cisco Email Security Appliance Content Filter Bypass Vulnerability
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Cisco Email Security Appliance Content Filter Bypass Vulnerability
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.
- Record
CVE-2019-1921- CVSS 3.0
- 5.8 Medium
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N - Weakness
- CWE-20
- Updated
- 2026-11-02
EUVDEUVD-2019-10478
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.
- Record
EUVD-2019-10478- CVSS 3.0
- 5.8 Medium
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-q86h-wvjc-7wh4
A vulnerability in the attachment scanning of Cisco AsyncOS Software for Cisco Email Security...
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.
- Record
GHSA-q86h-wvjc-7wh4- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-20
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2019-1921- CVSS 3.0
- 5.8 Medium
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N - CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:P/A:N - Weakness
- CWE-20
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2019-1921 is a medium vulnerability (CVSS 5.8) in Cisco Email Security Appliance (esa), published July 6, 2019. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.41%, the 72nd percentile. No source names a fixed version.