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.

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.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Cisco Cisco IOS XE Software affected
Version Status Constraints
16.9.1 affected —
16.9.2 affected —
16.9.1a affected —
16.9.1b affected —
16.9.1s affected —
16.9.3 affected —
16.9.4 affected —
16.9.3a affected —
16.9.5 affected —
16.9.5f affected —
16.9.6 affected —
16.9.7 affected —
16.9.8 affected —
16.10.1 affected —
16.10.1a affected —
16.10.1b affected —
16.10.1s affected —
16.10.1c affected —
16.10.1e affected —
16.10.1d affected —
16.10.2 affected —
16.10.1f affected —
16.10.1g affected —
16.10.3 affected —
16.11.1 affected —
16.11.1a affected —
16.11.1b affected —
16.11.2 affected —
16.11.1s affected —
16.12.1 affected —
16.12.1s affected —
16.12.1a affected —
16.12.1c affected —
16.12.1w affected —
16.12.2 affected —
16.12.1y affected —
16.12.2a affected —
16.12.3 affected —
16.12.8 affected —
16.12.2s affected —
16.12.1x affected —
16.12.1t affected —
16.12.4 affected —
16.12.3s affected —
16.12.3a affected —
16.12.4a affected —
16.12.5 affected —
16.12.6 affected —
16.12.1z1 affected —
16.12.5a affected —
16.12.5b affected —
16.12.1z2 affected —
16.12.6a affected —
16.12.7 affected —
16.12.9 affected —
16.12.10 affected —
16.12.10a affected —
16.12.11 affected —
16.12.12 affected —
16.12.13 affected —
16.12.14 affected —
16.12.15 affected —
17.1.1 affected —
17.1.1a affected —
17.1.1s affected —
17.1.1t affected —
17.1.3 affected —
17.2.1 affected —
17.2.1r affected —
17.2.1a affected —
17.2.1v affected —
17.2.2 affected —
17.2.3 affected —
17.3.1 affected —
17.3.2 affected —
17.3.3 affected —
17.3.1a affected —
17.3.1w affected —
17.3.2a affected —
17.3.1x affected —
17.3.1z affected —
17.3.4 affected —
17.3.5 affected —
17.3.4a affected —
17.3.6 affected —
17.3.4b affected —
17.3.4c affected —
17.3.5a affected —
17.3.5b affected —
17.3.7 affected —
17.3.8 affected —
17.3.8a affected —
17.4.1 affected —
17.4.2 affected —
17.4.1a affected —
17.4.1b affected —
17.4.2a affected —
17.5.1 affected —
17.5.1a affected —
17.6.1 affected —
17.6.2 affected —
17.6.1w affected —
17.6.1a affected —
17.6.1x affected —
17.6.3 affected —
17.6.1y affected —
17.6.1z affected —
17.6.3a affected —
17.6.4 affected —
17.6.1z1 affected —
17.6.5 affected —
17.6.6 affected —
17.6.6a affected —
17.6.5a affected —
17.6.7 affected —
17.6.8 affected —
17.6.8a affected —
17.7.1 affected —
17.7.1a affected —
17.7.1b affected —
17.7.2 affected —
17.10.1 affected —
17.10.1a affected —
17.10.1b affected —
17.8.1 affected —
17.8.1a affected —
17.9.1 affected —
17.9.1w affected —
17.9.2 affected —
17.9.1a affected —
17.9.1x affected —
17.9.1y affected —
17.9.3 affected —
17.9.2a affected —
17.9.1x1 affected —
17.9.3a affected —
17.9.4 affected —
17.9.1y1 affected —
17.9.5 affected —
17.9.4a affected —
17.9.5a affected —
17.9.5b affected —
17.9.6 affected —
17.9.6a affected —
17.9.5e affected —
17.9.5f affected —
17.11.1 affected —
17.11.1a affected —
17.12.1 affected —
17.12.1w affected —
17.12.1a affected —
17.12.1x affected —
17.12.2 affected —
17.12.3 affected —
17.12.2a affected —
17.12.1y affected —
17.12.1z affected —
17.12.4 affected —
17.12.3a affected —
17.12.1z1 affected —
17.12.1z2 affected —
17.12.4a affected —
17.12.4b affected —
17.12.1z3 affected —
17.12.1z4 affected —
17.12.1z5 affected —
17.12.1z6 affected —
17.13.1 affected —
17.13.1a affected —
17.14.1 affected —
17.14.1a affected —
17.15.1 affected —
17.15.1w affected —
17.15.1a affected —
17.15.1b affected —
17.15.1x affected —
17.15.1z affected —
17.15.1y affected —
17.16.1 affected —
17.16.1a affected —

No data.

No data.

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No data.

Project Subscriptions

No data.

Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-tls-dos-TVgLDEZL cve-icon cve-icon
History

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'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: cisco

Published:

Updated: 2026-03-25T16:04:48.379Z

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

Link: CVE-2026-20004

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

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

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

Link: CVE-2026-20004

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-03-25T21:30:53Z

Weaknesses