CVE-2026-25075
HighCVSS 7.5Exploitation Probability (EPSS)
Elevated risk59th percentile - higher than 59% of all known CVEs
Summary
strongSwan versions 4.5.0 prior to 6.0.5 contain an integer underflow vulnerability in the EAP-TTLS AVP parser. Unauthenticated remote attackers can send crafted AVP data with invalid length fields during IKEv2 authentication, causing the charon IKE daemon to crash.
Risk Assessment
Attackers can cause a denial of service (DoS) by triggering excessive memory allocation or a NULL pointer dereference, crashing the VPN service. The vulnerability is remotely exploitable without authentication.
Recommendation
Upgrade strongSwan to version 6.0.5 or later immediately. If upgrading is not possible, restrict IKEv2 service access to trusted networks only.
Other vulnerabilities in strongSwan
See all- CVE-2017-9023High
The ASN.1 parser in strongSwan before version 5.5.3 improperly handles CHOICE types when the x509 plugin is enabled, allowing remote attackers to cause a denial of service (infinite loop) via a crafted certificate.
- CVE-2015-3991Critical
strongSwan versions 5.2.2 and 5.3.0 allow remote attackers to cause a denial of service (daemon crash) or execute arbitrary code.
- CVE-2026-47895High
In strongSwan before 6.0.7, identity parsing/cloning is mishandled. Parsed EAP-Identities that result in an empty but non-NULL encoding are not correctly cloned and trigger a double-free once the duplicates are destroyed.
Original NVD description (English source)
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.