Vulnerability · Published Mar 25, 2026 · Assigned by cisco
CVE-2026-20004
High 7.4
In plain English
A high-severity security flaw in Cisco IOS XE Software from Cisco. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities).
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Cisco | Cisco IOS XE Software | 16.9.116.9.216.9.1a16.9.1b16.9.1s16.9.316.9.416.9.3a |
Weakness: CWE-771 · Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H