What’s Vulnerable › Vulnerabilities

CVE-2021-1352: Cisco IOS XE Software DECnet Phase IV/OSI Denial of Service Vulnerability

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-03-24 · updated 2026-06-17
• Weakness: CWE-823

Description

A vulnerability in the DECnet Phase IV and DECnet/OSI protocol processing of Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to insufficient input validation of DECnet traffic that is received by an affected device. An attacker could exploit this vulnerability by sending DECnet traffic to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

Affected products

• Cisco IOS XE: 16.4.1, 16.4.2, 16.4.3, 16.5.1, 16.5.1a, 16.5.1b (+83)

References

• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-decnet-dos-cuPWDkyL
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-decnet-dos-cuPWDkyL

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