SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2020-3516

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.

MEDIUM 4.3EPSS 1.67%

Does this matter?

Lower severity and a low EPSS score (1.67%). Track it; it rarely justifies an emergency change on its own.

Description

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.

CVSS 3.1
4.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
EPSS
1.67% probability · 77th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-20
Affected
cisco/ios xe
Source
psirt@cisco.com
EPSS trend
0%3%5%26 October 2026: 1.67%26 October 202626 October 2026

EPSS 1.7% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.