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.

Metrics

No CVSS v4.0

Attack Vector Adjacent Network

Attack Complexity Low

Privileges Required None

Scope Changed

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploitation none

Automatable no

Technical Impact partial

Affected Vendors & Products

Vendors Products
Cisco
  • Ios Xe Software

No data.

No data.

References
Link Providers
https://www.spirityenterprise.com/pentest spirity
https://www.spirityenterprise.com/managed-detection-response spirity
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-tls-dos-TVgLDEZL cve-icon cve-icon
History

Thu, 26 Mar 2026 18:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Thu, 26 Mar 2026 12:00:00 +0000

Type Values Removed Values Added
First Time appeared Cisco
Cisco ios Xe Software
Vendors & Products Cisco
Cisco ios Xe Software

Wed, 25 Mar 2026 22:00:00 +0000

Type Values Removed Values Added
Title TLS Memory Exhaustion in Cisco IOS XE Software Causing Denial of Service

Wed, 25 Mar 2026 16:15:00 +0000

Type Values Removed Values Added
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.
Weaknesses CWE-771
References
Metrics cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H'}
cve-icon MITRE

Status: PUBLISHED

Assigner: cisco

Published:

Updated: 2026-03-26T17:38:43.815Z

Reserved: 2025-10-08T11:59:15.349Z

Link: CVE-2026-20004

cve-icon Vulnrichment

Updated: 2026-03-26T17:38:39.794Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-03-25T16:16:10.520

Modified: 2026-03-26T15:13:33.940

Link: CVE-2026-20004

cve-icon Redhat

No data.