Vulnerability · Published Aug 5, 2026 · Assigned by cisco
CVE-2026-20028Cisco Terminal Services Agent Firewall Rules Bypass Vulnerability
Medium 5.0
In plain English
A medium-severity security flaw in Cisco Terminal Services Agent from Cisco. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities).
Official description
A vulnerability in the network driver of Cisco Terminal Service (TS) Agent could allow an authenticated, remote attacker to bypass firewall rules that are associated with the account of the attacker. This vulnerability is due to an incorrect mapping of network connections to user accounts. An attacker with at least user-level credentials could exploit this vulnerability by sending crafted network traffic to an affected device. A successful exploit could allow the attacker to inherit the firewall rules associated with a different user in the system.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Cisco | Cisco Terminal Services Agent | TSAgent-1.3TSAgent-1.4.2TSAgent-1.2TSAgent-1.4TSAgent-1.0TSAgent-1.4.1TSAgent-1.1 |
Weakness: CWE-266 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N