CVE-2019-1905
mediumpriority · track · 23EPSS 0.014 · 72 %ileEURUUSEPSS · scored 2026-10-27
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.
remediations
Vendor fix, mitigation, or workaround guidance, as published by each source.
A vendor fix is available.
- FixedCisco Email Security Appliance (ESA)cisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (7)
Products and version ranges known to be affected.
advisories (1)
Vendor and ecosystem advisories describing this.
- cisco-sa-20190619-esa-bypassCisco Email Security Appliance GZIP Content Filter Bypass Vulnerability2019-06-19csaf · cisco_csafUS
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. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190619-esa-bypass ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190619-esa-bypass"]
also known as (4)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (13)
External citations — patches, advisories, analysis.
- http://www.cisco.com/cnnvd
- https://lists.debian.org/debian-lts-announce/2020/01/msg00013.htmlcnnvd
- https://nvd.nist.gov/vuln/detail/CVE-2019-1905cnnvd
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190619-esa-bypasscnnvd
- https://vigilance.fr/vulnerability/Cisco-Email-Security-Appliance-privilege-escalation-via-GZIP-Content-Filter-Bypass-29570cnnvd
- https://www.auscert.org.au/bulletins/ESB-2019.2203/cnnvd
- https://www.auscert.org.au/bulletins/ESB-2020.0200/cnnvd
- https://www.auscert.org.au/bulletins/ESB-2020.0766/cnnvd
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