Cisco Terminal Services Agent Firewall Rules Bypass Vulnerability

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-20028
StatePUBLISHED
Assignercisco
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-05 17:16:46 UTC
Updated2026-10-23 21:10:00 UTC
DescriptionA 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.

Risk And Classification

Primary CVSS: v3.1 5 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N

EPSS: 0.003460000 probability, percentile 0.269620000 (date 2026-10-23)

Problem Types: CWE-266 | CWE-266 Incorrect Privilege Assignment

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N
3.1CNACVSSV3_15MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Cisco Cisco Terminal Services Agent affected TSAgent-1.3 Not specified
CNA Cisco Cisco Terminal Services Agent affected TSAgent-1.4.2 Not specified
CNA Cisco Cisco Terminal Services Agent affected TSAgent-1.2 Not specified
CNA Cisco Cisco Terminal Services Agent affected TSAgent-1.4 Not specified
CNA Cisco Cisco Terminal Services Agent affected TSAgent-1.0 Not specified
CNA Cisco Cisco Terminal Services Agent affected TSAgent-1.4.1 Not specified
CNA Cisco Cisco Terminal Services Agent affected TSAgent-1.1 Not specified

References

ReferenceSourceLinkTags
sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ts-age... [email protected] sec.cloudapps.cisco.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

Exploits

CNA: The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.

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