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Fencer Vulns
medium 5.6

CVE-2026-78135 json

libcharon in strongSwan 5.9.7 through 6.0.7 mishandles behavioral workflow in the IKEv2 state machine.

published 2026-09-11 59 d ago modified 2026-09-16 53 d ago also EUVD-2026-75921

cvss
5.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 36%
public exploits
0
none known

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.

Patch / fix

  • strongSwan strongSwan 6.1.0
  • strongswan Debian 12 5.9.8-5+deb12u6
  • strongswan Debian 13 6.0.1-6+deb13u7
  • strongswan Debian 14 6.1.0-1

debian advisories DEBIAN-CVE-2026-78135

  • strongswan Ubuntu 22.04 LTS 5.9.5-2ubuntu2.8
  • strongswan Ubuntu 24.04 LTS 5.9.13-2ubuntu4.24.04.5
  • strongswan Ubuntu 26.04 LTS 6.0.4-1ubuntu3.2

ubuntu advisories UBUNTU-CVE-2026-78135

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • strongswan SLES for SAP applications 16.0, SLES 16.0 6.0.6-160000.3.1
  • strongswan SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +1 more 5.9.11-150400.19.40.2
  • strongswan SLE Workstation Extension 15 SP7, SLE Module for Package Hub 15 SP7, SLE Module for Basesystem 15 SP7 5.9.14-150700.3.21.2

suse advisories SUSE-SU-2026:24199-1SUSE-SU-2026:4146-1SUSE-SU-2026:4115-1

  • strongswan openSUSE Leap 16.0 6.0.6-160000.3.1
  • strongswan openSUSE Tumbleweed 6.1.0-1.1

opensuse advisories openSUSE-SU-2026:22050-1openSUSE-SU-2026:11749-1

  • strongswan Azure Linux 3.0 5.9.14-11

azure linux advisories AZL-100049

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
55 d ago

Exploit prediction

0.42% chance of exploitation in the next 30 days, higher than 36% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.6 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
NVD 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Affected products

  • strongSwan strongSwan

Classification

Weakness
  • CWE-841 Improper Enforcement of Behavioral Workflow

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.