CVE-2026-78123: Medium severity strongSwan Strongswan vulnerability

Q: Which deployments are affected?

Deployments using strongSwan versions 5.0.2 through 6.0.7 are affected when the openssl plugin performs PKCS#7 parsing.

Q: What does an attacker need to exploit this issue?

The published vector indicates network reachability, no privileges, and no user interaction are required. Exploitation has high attack complexity.

Q: What is the likely impact?

The vulnerability affects availability only; confidentiality and integrity are not impacted according to the provided severity vector. Successful exploitation can cause a denial of service.

Q: What version should be used to remediate the issue?

The affected range ends at 6.0.7, and the provided release reference is for strongSwan 6.1.0.

Published Sep 11, 2026

Updated

strongSwan 5.0.2 through 6.0.7 has an Expired Pointer Dereference in PKCS#7 parsing in the openssl plugin.

Affected Software

6 affected componentsFixes available

strongSwan Strongswan>=5.0.2<=6.0.7

strongSwan Strongswan>=5.0.2<6.1.0

debian/strongswan<5.9.8-5+deb12u6

5.9.8-5+deb12u6

debian/strongswan<6.0.1-6+deb13u7

6.0.1-6+deb13u7

debian/strongswan<6.1.0-1

6.1.0-1

debian/strongswan<=5.9.8-5+deb12u5, <=6.0.1-6+deb13u6

5.9.8-5+deb12u66.0.1-6+deb13u76.1.0-2

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade debian/strongswan to a version that resolves this vulnerability.
Fixed in 5.9.8-5+deb12u6
Upgrade
Upgrade debian/strongswan to a version that resolves this vulnerability.
Fixed in 6.0.1-6+deb13u7
Upgrade
Upgrade debian/strongswan to a version that resolves this vulnerability.
Fixed in 6.1.0-1
Upgrade
Upgrade debian/strongswan to a version that resolves this vulnerability.
Fixed in 5.9.8-5+deb12u6Fixed in 6.0.1-6+deb13u7Fixed in 6.1.0-2

Event History

Sep 11, 2026

CVE Published

via MITRE·01:26 AM

Data Sourced

via MITRE·01:26 AM

DescriptionSeverityWeakness

Data Sourced

via NVD·02:18 AM

RemedyDescriptionSeverityWeaknessAffected Software

Data Sourced

via OSV·02:18 AM

DescriptionSeverityAffected Software

Parent advisories

This vulnerability appears in the following advisories.

DSA-6487

Peer vulnerabilities

Found alongside the following vulnerabilities.

DLA-4879-1

Frequently Asked Questions

Which deployments are affected?

Deployments using strongSwan versions 5.0.2 through 6.0.7 are affected when the openssl plugin performs PKCS#7 parsing.

What does an attacker need to exploit this issue?

The published vector indicates network reachability, no privileges, and no user interaction are required. Exploitation has high attack complexity.

What is the likely impact?

The vulnerability affects availability only; confidentiality and integrity are not impacted according to the provided severity vector. Successful exploitation can cause a denial of service.

What version should be used to remediate the issue?

The affected range ends at 6.0.7, and the provided release reference is for strongSwan 6.1.0.

CVE-2026-78123: Medium severity strongSwan Strongswan vulnerability

Affected Software

Remediation

Event History

Parent advisories

Peer vulnerabilities

Frequently Asked Questions

Which deployments are affected?

What does an attacker need to exploit this issue?

What is the likely impact?

What version should be used to remediate the issue?

Company

Resources

Contact