Infinite loop in strongSwan - CVE-2026-78132

Vulnerability identifier: #VU151586

CSH Severity: Medium

CVSS v4: 8.7 [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]

CVE-ID: CVE-2026-78132

CWE-ID: CWE-835

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to an infinite loop in the x509 plugin's ietfAttrSyntax ASN.1 parser when parsing a crafted X.509 attribute certificate received in an IKEv2 CERT payload. A remote attacker can send a crafted attribute certificate containing an unexpected or malformed attribute value to cause a denial of service.

Only installations that load the x509 plugin are affected.

strongSwan
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server 15 SP5
Debian Linux
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise Workstation Extension 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Desktop 15
SUSE Package Hub 15
Basesystem Module
openSUSE Leap
Ubuntu
strongswan-mysql
strongswan-nm-debuginfo
strongswan-sqlite-debuginfo
strongswan-nm
strongswan-sqlite
strongswan-mysql-debuginfo
strongswan-doc
strongswan-debugsource
strongswan-libs0
strongswan-hmac
strongswan-ipsec
strongswan
strongswan-debuginfo
strongswan-libs0-debuginfo
strongswan-ipsec-debuginfo
strongswan (Ubuntu package)
strongswan (Debian package)

Install security update from vendor's website.

strongSwan - update to 6.1.0
strongswan-mysql - addressed in versions 5.9.11-150400.19.40.2, 5.9.11-150500.5.28.2, 5.9.12-150600.3.23.2
strongswan-nm-debuginfo - addressed in versions 5.9.11-150400.19.40.2, 5.9.11-150500.5.28.2, 5.9.12-150600.3.23.2, 5.9.14-150700.3.21.2
strongswan-sqlite-debuginfo - addressed in versions 5.9.11-150400.19.40.2, 5.9.11-150500.5.28.2, 5.9.12-150600.3.23.2
strongswan-nm - addressed in versions 5.9.11-150400.19.40.2, 5.9.11-150500.5.28.2, 5.9.12-150600.3.23.2, 5.9.14-150700.3.21.2
strongswan-sqlite - addressed in versions 5.9.11-150400.19.40.2, 5.9.11-150500.5.28.2, 5.9.12-150600.3.23.2
strongswan-mysql-debuginfo - addressed in versions 5.9.11-150400.19.40.2, 5.9.11-150500.5.28.2, 5.9.12-150600.3.23.2
strongswan-doc - addressed in versions 5.9.11-150400.19.40.2, 5.9.11-150500.5.28.2, 5.9.12-150600.3.23.2, 5.9.14-150700.3.21.2
strongswan-debugsource - addressed in versions 5.9.11-150400.19.40.2, 5.9.11-150500.5.28.2, 5.9.12-150600.3.23.2, 5.9.14-150700.3.21.2
strongswan-libs0 - addressed in versions 5.9.11-150400.19.40.2, 5.9.11-150500.5.28.2, 5.9.12-150600.3.23.2, 5.9.14-150700.3.21.2
strongswan-hmac - addressed in versions 5.9.11-150400.19.40.2, 5.9.11-150500.5.28.2, 5.9.12-150600.3.23.2, 5.9.14-150700.3.21.2
strongswan-ipsec - addressed in versions 5.9.11-150400.19.40.2, 5.9.11-150500.5.28.2, 5.9.12-150600.3.23.2, 5.9.14-150700.3.21.2
strongswan - addressed in versions 5.9.11-150400.19.40.2, 5.9.11-150500.5.28.2, 5.9.12-150600.3.23.2, 5.9.14-150700.3.21.2
strongswan-debuginfo - addressed in versions 5.9.11-150400.19.40.2, 5.9.11-150500.5.28.2, 5.9.12-150600.3.23.2, 5.9.14-150700.3.21.2
strongswan-libs0-debuginfo - addressed in versions 5.9.11-150400.19.40.2, 5.9.11-150500.5.28.2, 5.9.12-150600.3.23.2, 5.9.14-150700.3.21.2
strongswan-ipsec-debuginfo - addressed in versions 5.9.11-150400.19.40.2, 5.9.11-150500.5.28.2, 5.9.12-150600.3.23.2, 5.9.14-150700.3.21.2
strongswan (Ubuntu package) - addressed in versions 5.9.5-2ubuntu2.8, 5.9.13-2ubuntu4.24.04.5, 6.0.4-1ubuntu3.2
strongswan (Debian package) - update to 6.0.1-6+deb13u7

• https://www.strongswan.org/blog/2026/09/07/strongswan-vulnerability-(cve-2026-78132).html

• Multiple vulnerabilities in strongSwan
• Debian update for strongswan
• SUSE update for strongswan
• SUSE update for strongswan
• SUSE update for strongswan
• Ubuntu update for strongswan
• SUSE update for strongswan