Vulnerability · Published Oct 6, 2021 · Assigned by cisco

CVE-2021-1534Cisco Email Security Appliance URL Filtering Bypass Vulnerability

Medium 5.8

In plain English

A medium-severity improper input validation in Cisco Email Security Appliance (ESA) from Cisco. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.1% (higher than 65% of all known vulnerabilities).

Severity (CVSS 3.1)5.8Medium

Exploit odds (30 days)1.1%top 35.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
Cisco	Cisco Email Security Appliance (ESA)	n/a

Weakness: CWE-20 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

References

20211006 Cisco Email Security Appliance URL Filtering Bypass Vulnerability vendor-advisory, x_refsource_CISCO