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Fencer Intel
medium 4.3

CVE-2020-3516 json

Cisco IOS XE Software Web UI Improper Input Validation Vulnerability

published 6y ago modified 4mo ago also EUVD-2020-24787

cvss
4.3
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.7%
EPSS 1.7% chance of exploitation in 30 days, percentile 76%
public exploits
0
none known

Summary

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.

Patch / fix

  • cisco ios_xe 16.9.6, 16.12.2, 17.1.1

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-22-300-03 updated cvss 4.3

Rockwell Automation Stratix Devices Containing Cisco IOS

  • Rockwell Automation Stratix Devices <16.12.01
    affected: mitigation “Rockwell Automation has addressed these vulnerabilities updates and encourages users to combine these updates with Rockwell Automation's Security Best Practices:” rockwellautomation.custhelp.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
last yr.

Exploit prediction

1.67% chance of exploitation in the next 30 days, higher than 76% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.0 4.3 CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
NVD 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
NVD 2.0 4.0 AV:N/AC:L/Au:S/C:N/I:N/A:P

Affected products

  • Cisco Cisco IOS XE Software

Classification

Weakness
  • CWE-20 Improper Input Validation
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.