How severe is CVE-2020-3137?

CVE-2020-3137 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2020-3137 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (56th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-3137?

CVE-2020-3137 affects Cisco Email Security Appliance. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-3137?

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

When was CVE-2020-3137 published?

CVE-2020-3137 was published on 2020-09-23 and last updated on 2026-06-17.

CVE-2020-3137

CVE-2020-3137 is a medium-severity vulnerability in Cisco Email Security Appliance with a CVSS 3.x base score of 6.1. 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-79.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 4.3
EPSS exploit prediction: 1% (56th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Cisco Email Security Appliance
Published: 2020-09-23
Last modified: 2026-06-17

Description

A vulnerability in the web-based management interface of Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the web-based management interface of an affected device. The vulnerability exists because the web-based management interface of the affected device does not properly validate user-supplied input. An attacker could exploit this vulnerability by persuading a user to click a malicious link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or to access sensitive, browser-based information.

Frequently asked questions

What is CVE-2020-3137?: A vulnerability in the web-based management interface of Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the web-based management interface of an affected device. The vulnerability exists because the web-based management interface of the affected device does not properly validate user-supplied input. An attacker could exploit this vulnerability by persuading a user to click a malicious link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or to access sensitive, browser-based information.
How severe is CVE-2020-3137?: CVE-2020-3137 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2020-3137 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (56th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-3137?: CVE-2020-3137 affects Cisco Email Security Appliance. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-3137?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-3137 published?: CVE-2020-3137 was published on 2020-09-23 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-email-sec-xss-EbjXuXwP

Affected products (1)

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

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