Cisco Email Security Appliance GZIP Content Filter Bypass Vulnerability

Description

A vulnerability in the GZIP decompression 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 GZIP-formatted files. An attacker could exploit this vulnerability by sending a malicious file inside a crafted GZIP-compressed file. A successful exploit could allow the attacker to bypass configured content filters that would normally drop the email.

Scores

EPSS (exploitation in 30 days)

1.4% · top 28% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: yes · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.8.

Weakness

• CWE-20 (opens in a new tab)All about CWE-20 and its CVEs

Affected products

• Cisco · Cisco Email Security Appliance (ESA)

  • affected 12.0

What to do

Exploitation: The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.

References (2)

• 20190619 Cisco Email Security Appliance GZIP Content Filter Bypass Vulnerability (opens in a new tab)vendor-advisoryx_refsource_CISCOx_transferred
• 108856 (opens in a new tab)vdb-entryx_refsource_BIDx_transferred

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2019-1905](https://trackcve.app/badge/CVE-2019-1905.svg)](https://trackcve.app/cve/CVE-2019-1905)

Record last updated 19 Nov 2024, 19:05 UTC.