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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.01%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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 4.0
- 8.7 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 1.01% probability · 61th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-191, CWE-476
- Source
- disclosure@vulncheck.com
References
- https://www.strongswan.org/blog/2026/03/23/strongswan-6.0.5-released.html
- https://www.strongswan.org/blog/2026/03/23/strongswan-vulnerability-(cve-2026-25075).html
- https://www.vulncheck.com/advisories/strongswan-eap-ttls-avp-parsing-integer-underflow
- https://y637f9qq2x.com/posts/cve-2026-25075/
- https://lists.debian.org/debian-lts-announce/2026/03/msg00016.html
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.