How severe is CVE-2019-1905?

CVE-2019-1905 has a CVSS 3.x base score of 5.8, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2019-1905 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-1905?

CVE-2019-1905 primarily affects Cisco Email Security Appliance. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-1905?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2019-1905 published?

CVE-2019-1905 was published on 2019-06-20 and last updated on 2026-06-17.

CVE-2019-1905

CVE-2019-1905 is a medium-severity vulnerability in Cisco Email Security Appliance with a CVSS 3.x base score of 5.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

Severity: Medium (CVSS 3.x base score 5.8)
CVSS v2: 5.0
EPSS exploit prediction: 1% (68th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Cisco Email Security Appliance
Published: 2019-06-20
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2019-1905?: 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.
How severe is CVE-2019-1905?: CVE-2019-1905 has a CVSS 3.x base score of 5.8, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2019-1905 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-1905?: CVE-2019-1905 primarily affects Cisco Email Security Appliance. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-1905?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2019-1905 published?: CVE-2019-1905 was published on 2019-06-20 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:cisco:email_security_appliance:11.1.2:*:*:*:*:*:*:*
cpe:2.3:a:cisco:email_security_appliance:12.0.0:*:*:*:*:*:*:*

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