Cisco Email Security Appliance MP3 Content Filter Bypass Vulnerability

published 2019-11-26 6 y ago modified 2026-06-17 4 mo ago also EUVD-2019-6865

cvss: 5.8; version 3.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 39%
public exploits: 0; none known

A vulnerability in the MP3 detection engine 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 validation of certain MP3 file types. An attacker could exploit this vulnerability by sending a crafted MP3 file through the targeted device. A successful exploit could allow the attacker to bypass configured content filters that would normally drop the email.

Patch / fix

fixed in 1

cisco email_security_appliance_firmware 13.0

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 23 mo ago (2024-11-19)

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.0	5.8	CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
NVD	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
NVD	2.0	4.3	AV:N/AC:M/Au:N/C:N/I:P/A:N

Affected products

Cisco Cisco Email Security Appliance (ESA)

Classification

Weakness

CWE-20 Improper Input Validation
CWE-345 Insufficient Verification of Data Authenticity

References

tools.cisco.com /security/center/content/CiscoSecurityAdvisory/cisco-sa-20191120-esa-mp3-bypass
vendor-advisory

Sources

CVE List CVE-2019-15971
NVD CVE-2019-15971

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary