Is CVE-2020-3516 being actively exploited?

CVE-2020-3516 is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

What is the CVSS score for CVE-2020-3516?

CVE-2020-3516 has a CVSS 3.1 base score of 4.3 (MEDIUM).

CVE-2020-3516

MEDIUM · CVSS 4.3EPSS 1.7%EU EUVD

A vulnerability in the web server authentication of Cisco IOS XE Software could allow an authenticated, remote attacker to crash the web server on the device. The vulnerability is due to insufficient input validation during authentication. An attacker could exploit this vulnerability by entering unexpected characters during a valid authentication. A successful exploit could allow the attacker to crash the web server on the device, which must be manually recovered by disabling and re-enabling the web server.

Key facts

CVSS score: 4.3 (v3.1)
Severity: MEDIUM
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Weakness (CWE): CWE-20
EPSS score: 1.7% (76th percentile)
In CISA KEV: No
In EU EUVD: Yes (EUVD-2020-24787)
Published: September 24, 2020
NVD last modified: June 17, 2026
Status: Modified

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2020-24787 in the EU Vulnerability Database. Last updated in EUVD on November 13, 2024.

View on the EU Vulnerability Database

Affected products

cisco / ios xe
cisco / ios xe

Certified products that may be affected

15 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.

Cisco ASR 900 Series and NCS4200 Series running IOS-XE 16.9 - Cisco Systems, Inc. - Common Criteria IC3S/MUM01/CISCO/cPP/0119/0016 - archived
Cisco Catalyst 9200L and 9400 Series Switches running IOS-XE 16.9 - Cisco Systems, Inc. - Common Criteria CCEVS-VR-VID-10972-2019 - archived
Cisco Aggregation Services Router 1004 (ASR1K) running IOS-XE 16.9 - Cisco Systems, Inc. - Common Criteria CCEVS-VR-VID-10950-2019 - archived
Cisco Catalyst 3650 and 3850 Series Switches running IOS-XE 16.9 - Cisco Systems, Inc. - Common Criteria CCEVS-VR-VID-10940-2019 - archived
Cisco Catalyst 4500 Series Wired Access Switches running IOS-XE 3.10 - Cisco Systems, Inc. - Common Criteria CCEVS-VR-10906-2018 - archived

See all 15 in the Security Certifications Explorer.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-WEB-UI-exNFmcPO(Vendor Advisory)

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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