CVE-2026-25075

strongSwan versions 4.5.0 prior to 6.0.5 contain an integer underflow vulnerability in the EAP-TTLS AVP parser that allows unauthenticated remote attackers to cause a denial of service by sending crafted AVP data with invalid length fields during IKEv2 authentication. Attackers can exploit the failure to validate AVP length fields before subtraction to trigger excessive memory allocation or NULL pointer dereference, crashing the charon IKE daemon.

strongSwan versions 4.5.0 prior to 6.0.5 contain an integer underflow vulnerability in the EAP-TTLS AVP parser that allows unauthenticated remote attackers to cause a denial of service by sending crafted AVP data with invalid length fields during IKEv2 authentication. Attackers can exploit the failure to validate AVP length fields before subtraction to trigger excessive memory allocation or NULL pointer dereference, crashing the charon IKE daemon.

strongSwan 4.5.0 < 6.0.5 EAP-TTLS AVP Parsing Integer Underflow. (CVE-2026-25075)

These are all security issues fixed in the strongswan-6.0.5-1.1 package on the GA media of openSUSE Tumbleweed.

This update for strongswan fixes the following issues:

Update to strongswan 6.0.4:

• CVE-2025-9615: NetworkManager File Access (bsc#1257359).
• CVE-2026-25075: Integer Underflow When Handling EAP-TTLS AVP (bsc#1259472).

Changes for strongswan:

• Fixed a vulnerability in the NetworkManager plugin that potentially allows using credentials of other local users. This vulnerability has been registered as CVE-2025-9615.
• The maximum supported length for section names in swanctl.conf has been increased to the upper limit of 256 characters that's enforced by VICI.
• Prevent a crash if a confused peer rekeys a Child SA twice before sending a delete.
• Fixed a memory leak if a peer's self-signed certificate is untrusted.

This update for strongswan fixes the following issues:

• CVE-2026-25075: Fixed integer underflow when handling EAP-TTLS AVP (bsc#1259472).

Other bug fixes:

-Fix rpm scripts to not break swanctl.conf use (bsc#1256442):

• Guard rpm migration scripts migrating strongswan.service using ipsec.conf on less than 5.8 to strongswan-starter.service by checking the ipsec.service alias provider.
• Call systemd macros for both, strongswan-starter and the strongswan service.

This update for strongswan fixes the following issues:

• CVE-2026-25075: Fixed integer underflow when handling EAP-TTLS AVP (bsc#1259472).

This update for strongswan fixes the following issues:

• CVE-2026-25075: Fixed integer underflow when handling EAP-TTLS AVP (bsc#1259472).

This update for strongswan fixes the following issues:

• CVE-2026-25075: Fixed integer underflow when handling EAP-TTLS AVP (bsc#1259472).

This update for strongswan fixes the following issue:

• CVE-2026-25075: integer underflow when handling EAP-TTLS AVP (bsc#1259472).

This update for strongswan fixes the following issues:

Update to strongswan 6.0.4:

• CVE-2025-9615: NetworkManager File Access (bsc#1257359).
• CVE-2026-25075: Integer Underflow When Handling EAP-TTLS AVP (bsc#1259472).

Changes for strongswan:

• Fixed a vulnerability in the NetworkManager plugin that potentially allows using credentials of other local users. This vulnerability has been registered as CVE-2025-9615.
• The maximum supported length for section names in swanctl.conf has been increased to the upper limit of 256 characters that's enforced by VICI.
• Prevent a crash if a confused peer rekeys a Child SA twice before sending a delete.
• Fixed a memory leak if a peer's self-signed certificate is untrusted.

Kazuma Matsumoto discovered that strongSwan incorrectly handled EAP-TTLS AVPs when using the eap-ttls plugin. An attacker could possibly use this issue to cause strongSwan to consume resources and crash, resulting in a denial of service.