CVE-2026-12254 PUBLISHED

Netskope Client Captive Portal WebView Persistence allowing SWG bypass issue

Assigner: Netskope
Reserved: 15.06.2026 Published: 19.10.2026 Updated: 19.10.2026

Netskope is notified about a potential gap in its agent (NSClient) where a system with Netskope Client while connecting to an access point with Captive Portal switches to a Network which already has internet connectivity, the Captive Portal does not close. This allows the possibility of abuse via the Captive Portal using a rogue access point to either access malicious sites or exfiltrate data.The issue impacts all versions prior to R142

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H
CVSS Score: 6.4

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	High
Attack Complexity	Low	Integrity	None	Integrity	High
Attack Requirements	None	Availability	None	Availability	High
Privileges Required	None
User Interaction	Active

CVSS 4.0

Product Status

Vendor	Netskope Inc.
Product	Netskope Client
Versions	Default: unaffected affected from 0 to 142 (excl.)

Solutions

Netskope has fixed the gap and released the patch as listed below: R142 and above R141 (141.1.7.2827 and above) R138 (138.1.15.2826 and above) R135 (135.1.7.2827 and above)

Credits

Loïc Croche (Independant security researcher) finder

References

https://www.netskope.com/resources/netskope-resources/netskope-security-advisory-nskpsa-2026-004

Problem Types

CWE-613 Insufficient session expiration CWE

Impacts

CAPEC-593 Session Hijacking