How severe is CVE-2020-3134?

CVE-2020-3134 has a CVSS 3.x base score of 6.5, 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 low.

Is CVE-2020-3134 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (61st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-3134?

CVE-2020-3134 affects Cisco Email Security Appliance. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-3134?

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

When was CVE-2020-3134 published?

CVE-2020-3134 was published on 2020-01-26 and last updated on 2026-06-17.

CVE-2020-3134

CVE-2020-3134 is a medium-severity vulnerability in Cisco Email Security Appliance with a CVSS 3.x base score of 6.5. 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 6.5)
CVSS v2: 6.4
EPSS exploit prediction: 1% (61st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Cisco Email Security Appliance
Published: 2020-01-26
Last modified: 2026-06-17

Description

A vulnerability in the zip decompression engine of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper validation of zip files. An attacker could exploit this vulnerability by sending an email message with a crafted zip-compressed attachment. A successful exploit could trigger a restart of the content-scanning process, causing a temporary DoS condition. This vulnerability affects Cisco AsyncOS Software for Cisco ESA releases earlier than 13.0.

Frequently asked questions

What is CVE-2020-3134?: A vulnerability in the zip decompression engine of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper validation of zip files. An attacker could exploit this vulnerability by sending an email message with a crafted zip-compressed attachment. A successful exploit could trigger a restart of the content-scanning process, causing a temporary DoS condition. This vulnerability affects Cisco AsyncOS Software for Cisco ESA releases earlier than 13.0.
How severe is CVE-2020-3134?: CVE-2020-3134 has a CVSS 3.x base score of 6.5, 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 low.
Is CVE-2020-3134 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (61st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-3134?: CVE-2020-3134 affects Cisco Email Security Appliance. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-3134?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-3134 published?: CVE-2020-3134 was published on 2020-01-26 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-esa-dos-87mBkc8n

Affected products (1)

cpe:2.3:a:cisco:email_security_appliance:*:*:*:*:*:*:*:*

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