TI-2026-16245 Aliases CVE-2026-20028 GHSA-6vj9-8q5m-xjpv

Cisco Terminal Services Agent Firewall Rules Bypass Vulnerability

LOW 23CWE-266Published 2026-08-05 · Updated 2026-08-05

Key facts

Attack vector: Network
Privileges required: Low
User interaction: None
Attack complexity: Low
Impact type: Privilege escalation
Confidentiality · integrity · availability: None · Low · None
Fix status: No fix listed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-266.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00346 28th percentileScored 2026-11-07

Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Cisco	Cisco Terminal Services Agent	TSAgent-1.3; TSAgent-1.4.2; TSAgent-1.2; TSAgent-1.4; TSAgent-1.0; TSAgent-1.4.1; TSAgent-1.1	—	No fix listed	CNA

Cisco Terminal Services Agent VendorCisco Affected TSAgent-1.3; TSAgent-1.4.2; TSAgent-1.2; TSAgent-1.4; TSAgent-1.0; TSAgent-1.4.1; TSAgent-1.1 Fixed in — No fix listed CNA

Remediation

No fixed version listed by the sources yet.

Timeline

2026-10-02 Threatist record created from CVE-2026-20028
2026-10-03 Alias added: GHSA-6vj9-8q5m-xjpv

References

Other 1

cisco-sa-ts-agent-fw-bypass-MYBTMrev

TI-2026-74174 Arbitrary file write in Cisco Secure Email Gateway via AMP feature KEVCVSS 3.1CRITICAL 9.8
TI-2026-53490 Cisco Catalyst SD-WAN Manager System Account Authorization Bypass Vulnerability KEVCVSS 3.1CRITICAL 9.8
TI-2026-53489 Cisco Secure Email Gateway SQL Injection Vulnerability KEVCVSS 3.1CRITICAL 9.8
TI-2026-53488 Cisco Identity Services Engine Authentication Bypass Vulnerability KEVCVSS 3.1CRITICAL 10.0
TI-2026-16388 Cisco Catalyst SD-WAN Controller Authentication Bypass Vulnerability KEVCVSS 3.1CRITICAL 10.0
TI-2026-16344 Cisco Secure Firewall Management Center Software Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 10.0

See all 7059 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences