CVE-2021-1534 : A vulnerability in the antispam protection mechanisms of Cisco AsyncOS Software

A vulnerability in the antispam protection mechanisms of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to bypass the URL reputation filters on an affected device. This vulnerability is due to improper processing of URLs. An attacker could exploit this vulnerability by crafting a URL in a particular way. A successful exploit could allow the attacker to bypass the URL reputation filters that are configured for an affected device, which could allow malicious URLs to pass through the device.

Published 2021-10-06 20:15:08

Updated 2021-10-14 22:59:23

Source Cisco Systems, Inc.

View at NVD, CVE.org

Vulnerability category: Input validation

Products affected by CVE-2021-1534

Cisco » Asyncos
Versions before (<) 14.0.1
cpe:2.3:o:cisco:asyncos:*:*:*:*:*:*:*:*
Matching versions
When used together with: Cisco » Email Security Appliance C170 » Version: N/A
When used together with: Cisco » Email Security Appliance C190 » Version: N/A
When used together with: Cisco » Email Security Appliance C380 » Version: N/A
When used together with: Cisco » Email Security Appliance C390 » Version: N/A
When used together with: Cisco » Email Security Appliance C680 » Version: N/A
When used together with: Cisco » Email Security Appliance C690 » Version: N/A
When used together with: Cisco » Email Security Appliance C690x » Version: N/A

Exploit prediction scoring system (EPSS) score for CVE-2021-1534

EPSS FAQ

0.13%

Probability of exploitation activity in the next 30 days EPSS Score History

~ 48 %

Percentile, the proportion of vulnerabilities that are scored at or less

CVSS scores for CVE-2021-1534

Base Score	Base Severity	CVSS Vector	Exploitability Score	Impact Score	Score Source
5.0	MEDIUM	AV:N/AC:L/Au:N/C:N/I:P/A:N	10.0	2.9	NIST
Access Vector: Network Access Complexity: Low Authentication: None Confidentiality Impact: None Integrity Impact: Partial Availability Impact: None
5.8	MEDIUM	CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N	3.9	1.4	Cisco Systems, Inc.
Attack Vector: Network Attack Complexity: Low Privileges Required: None User Interaction: None Scope: Changed Confidentiality: None Integrity: Low Availability: None
5.3	MEDIUM	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N	3.9	1.4	NIST
Attack Vector: Network Attack Complexity: Low Privileges Required: None User Interaction: None Scope: Unchanged Confidentiality: None Integrity: Low Availability: None

CWE ids for CVE-2021-1534

CWE-20 Improper Input Validation

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

Assigned by: ykramarz@cisco.com (Secondary)

References for CVE-2021-1534

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

Cisco Email Security Appliance URL Filtering Bypass Vulnerability
Vendor Advisory

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Vulnerability Details : CVE-2021-1534

Products affected by CVE-2021-1534

Exploit prediction scoring system (EPSS) score for CVE-2021-1534

CVSS scores for CVE-2021-1534

CWE ids for CVE-2021-1534

References for CVE-2021-1534