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
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 products (1)
- Cisco · Cisco IOS XE Software
Vendor advisory
cisco-sa-iosxe-tls-dos-TVgLDEZL
Cisco IOS XE Software TLS Memory Exhaustion Denial of Service Vulnerability
Cisco’s rating: High (advisory CVSS 7.4) · Published Mar 25, 2026
Bug IDs: CSCwk59707 , CSCwm80596
The vendor’s rating applies to the whole advisory and can differ from this CVE’s own CVSS severity. Where this comes from