CVE-2026-20004

A vulnerability in the TLS library of Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to exhaust the available memory of an affected device. This vulnerability is due to imp

Severity
High 7.4
CVSS 3.1
Exploited
Not listed
EPSS
0.002
7.6th percentile
Discovered by
Third party
Published by the vendor
Published
Mar 25, 2026
Assigned by cisco

Description

A vulnerability in the TLS library of Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to exhaust the available memory of an affected device. This vulnerability is due to improper management of memory resources during TLS connection setup. An attacker could exploit this vulnerability by repeatedly triggering the conditions that cause the memory increase. This could be done in a variety of ways, such as by repeatedly attempting Extensible Authentication Protocol (EAP) authentication when local EAP is enabled on an affected device or by using a machine-in-the-middle attack and resetting TLS connections between the affected device and other devices. A successful exploit could allow the attacker to exhaust the available memory on an affected device, resulting in an unexpected reload and a denial of service (DoS) condition.

Weakness: CWE-771

Affected products

Vendor Product Category Matched by
Cisco Cisco IOS XE Software Routing & Switching cna-assigner
Vendor-reported affected versions (1)
  • Cisco · Cisco IOS XE Software