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.
Published Mar 25, 2026 · updated Sep 28, 2026 · cisco ios xe
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.
Code
The project this record applies to. Exploit listings stay in References.
No public source repository is identified for this product.
Timeline
Detection, updates, and resolution for this record.
Mar 25, 2026 · NIST NVD
Detected
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 i
Sep 28, 2026 · NIST NVD
Updated
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 i
Affected
- cpe cisco/ios xe16.9.1
- cpe cisco/ios xe16.9.1a
- cpe cisco/ios xe16.9.1b
- cpe cisco/ios xe16.9.1s
- cpe cisco/ios xe16.9.2
- cpe cisco/ios xe16.9.3
- cpe cisco/ios xe16.9.3a
- cpe cisco/ios xe16.9.4
Sources
- CVE.orgVulnerability recordCVE-2026-20004
Official CVE identifier
cve.org - NIST NVDVulnerability recordCVE-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 improper management of memory resources during TLS connection setup. An attacker co
nvd.nist.gov