CVE-2024-20312

Severity: high (CVSS 7.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-03-27 · updated 2026-06-17
Weakness: CWE-476

Description

A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) protocol of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient input validation when parsing an ingress IS-IS packet. An attacker could exploit this vulnerability by sending a crafted IS-IS packet to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition. Note: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device and have formed an adjacency.

Affected products

Cisco IOS: 15.0(1)ex, 15.1(1)sy, 15.1(1)sy1, 15.1(1)sy2, 15.1(1)sy3, 15.1(1)sy4 (+420)
Cisco IOS XE: 3.2.0se, 3.2.1se, 3.2.2se, 3.2.3se, 3.3.0se, 3.3.0xo (+379)

References

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