---
id: CVE-2026-78135
title: >-
  libcharon in strongSwan 5.9.7 through 6.0.7 mishandles behavioral workflow in
  the IKEv2 state machine
summary: "libcharon in strongSwan 5.9.7 through 6.0.7 mishandles behavioral workflow in the IKEv2 state machine. Because\_CREATE_CHILD_SA requests are mishandled, there can be an authentication bypass."
severity: medium
cvss: 5.6
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L'
cwe:
  - CWE-841
vendor: strongswan
product: strongswan
affected:
  - 'strongswan >= 5.9.7, <= 6.0.7'
published: '2026-09-11'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T19:37:30.467'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-78135'
references:
  - url: 'https://github.com/strongswan/strongswan/releases/tag/6.1.0'
    label: cve@mitre.org
  - url: >-
      https://www.strongswan.org/blog/2026/09/07/strongswan-vulnerability-(cve-2026-78135).html
    label: cve@mitre.org
tags:
  - nvd
  - cve.org
epss: 0.00362
epssPercentile: 0.27405
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-15T15:32:40.015957Z'
ingestedAt: '2026-09-12T18:50:07.998Z'
---

## Overview

libcharon in strongSwan 5.9.7 through 6.0.7 mishandles behavioral workflow in the IKEv2 state machine. Because CREATE_CHILD_SA requests are mishandled, there can be an authentication bypass.

## Affected

- `strongswan >= 5.9.7, <= 6.0.7`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.