What’s Vulnerable › Vulnerabilities

CVE-2021-1288: Cisco IOS XR Software Enf Broker Denial of Service Vulnerability

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-02-04 · updated 2026-06-17
• Weakness: CWE-399

Description

Multiple vulnerabilities in the ingress packet processing function of Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. For more information about these vulnerabilities, see the Details section of this advisory.

Affected products

• Cisco IOS XR Software: from 5.0.0 before 5.2.6; from 5.3.0 before 5.3.4; from 6.0.0 before 6.0.2 — fixed in 5.2.6, 5.3.4, 6.0.2

How to fix

Upgrade to a fixed version: Cisco IOS XR Software 5.2.6, 5.3.4, 6.0.2. Check the vendor advisory for mitigations.

References

• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-dos-WwDdghs2
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-dos-WwDdghs2

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