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

Q: What is CVE-2026-25075?

CVE-2026-25075 is a high-severity vulnerability in strongSwan, published on 23 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Q: Is CVE-2026-25075 being exploited?

There is no known exploitation of CVE-2026-25075 in the wild and no public exploit code.

High 8.7 Published 23 Mar 2026 Updated 14 Jul 2026

Unauthenticated remote attackers can crash the strongSwan IKE daemon via crafted EAP-TTLS AVP data, causing denial of service.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-25075?

CVE-2026-25075 is a high-severity vulnerability in strongSwan, published on 23 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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.

Weakness: CWE-476, CWE-191

Which versions are affected by CVE-2026-25075?

Linux distribution packages (17)

`strongswan` SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	All versions	`5.9.11-150400.19.26.1`
`strongswan` SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS	All versions	`5.9.11-150400.19.26.1`
`strongswan` SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS	All versions	`5.9.11-150500.5.14.1`
`strongswan` SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS	All versions	`5.9.11-150500.5.14.1`
`strongswan` SUSE:Linux Enterprise Module for Basesystem 15 SP7	All versions	`5.9.14-150700.3.9.1`
`strongswan` SUSE:Linux Enterprise Module for Package Hub 15 SP7	All versions	`5.9.14-150700.3.9.1`
`strongswan` SUSE:Linux Enterprise Server 12 SP5-LTSS	All versions	`5.1.3-26.32.1`
`strongswan` SUSE:Linux Enterprise Server 15 SP4-LTSS	All versions	`5.9.11-150400.19.26.1`
`strongswan` SUSE:Linux Enterprise Server 15 SP5-LTSS	All versions	`5.9.11-150500.5.14.1`
`strongswan` SUSE:Linux Enterprise Server 15 SP6-LTSS	All versions	`5.9.12-150600.3.11.1`
`strongswan` SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5	All versions	`5.1.3-26.32.1`
`strongswan` SUSE:Linux Enterprise Server for SAP Applications 15 SP4	All versions	`5.9.11-150400.19.26.1`
`strongswan` SUSE:Linux Enterprise Server for SAP Applications 15 SP5	All versions	`5.9.11-150500.5.14.1`
`strongswan` SUSE:Linux Enterprise Server for SAP Applications 15 SP6	All versions	`5.9.12-150600.3.11.1`
`strongswan` SUSE:Linux Enterprise Workstation Extension 15 SP7	All versions	`5.9.14-150700.3.9.1`
`strongswan` openSUSE:Leap 15.6	All versions	`5.9.12-150600.3.11.1`
`strongswan` openSUSE:Tumbleweed	All versions	`6.0.5-1.1`

How do I fix CVE-2026-25075?

Upgrade to a fixed version.

Is CVE-2026-25075 being exploited?

There is no known exploitation of CVE-2026-25075 in the wild and no public exploit code.

Public exploit code: 1 proofs of concept on GitHub.

Sources

Also known as AZL-80300, DEBIAN-CVE-2026-25075, DLA-4512-1, DSA-6176-1, GHSA-frr2-5qjr-h4hw, MGASA-2026-0072 and 8 more.