Authentication Bypass by Spoofing in strongSwan - CVE-2026-78134
Published: September 22, 2026
Vulnerability identifier: #VU151584
CSH Severity: Low
CVSS v4: 7.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-78134
CWE-ID: CWE-290
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to bypass authorization controls by impersonating another user.
The vulnerability exists due to improper authentication of inner EAP identities in the eap-peap and eap-ttls plugins when processing tunneled EAP authentication. A remote user can authenticate with valid credentials while claiming another user's identity during the outer EAP-Identity exchange to bypass authorization controls by impersonating another user.
Exploitation requires the use of EAP-PEAP or EAP-TTLS tunneling authentication protocols.
Affected software
strongSwan
Debian Linux
strongswan (Debian package)
Debian Linux
strongswan (Debian package)
How to mitigate CVE-2026-78134
Install security update from vendor's website.
strongSwan - update to 6.1.0
strongswan (Debian package) - update to 6.0.1-6+deb13u7
strongswan (Debian package) - update to 6.0.1-6+deb13u7