CVE-2026-25075 PUBLISHED

strongSwan 4.5.0 < 6.0.5 EAP-TTLS AVP Parsing Integer Underflow

Assigner: VulnCheck
Reserved: 28.01.2026 Published: 23.03.2026 Updated: 23.03.2026

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.

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS Score: 8.7

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

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS Score: 7.5

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	None
Privileges Required	None	Integrity Impact	None
User Interaction	None	Availability Impact	High

CVSS 3.1

Product Status

Vendor	strongSwan
Product	strongSwan
Versions	Default: unaffected affected from 4.5.0 to 6.0.5 (excl.)

Credits

Kazuma Matsumoto, a security researcher at GMO Cybersecurity by IERAE, Inc. finder
VulnCheck coordinator

References

Problem Types

CWE-191 Integer underflow (wrap or wraparound) CWE
CWE-476 NULL pointer dereference CWE