CVE-2026-78123 Use after free in strongSwan

Medium 5.9 Published 11 Sep 2026 Updated 15 Sep 2026

An attacker can trigger a use-after-free vulnerability in strongSwan's PKCS#7 parser, potentially causing a crash or executing arbitrary code.

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

What is CVE-2026-78123?

CVE-2026-78123 is a medium-severity use after free vulnerability in strongSwan, published on 11 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

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

Weakness: CWE-825

Which versions are affected by CVE-2026-78123?

It affects 1 product.

Products include Strongswan Strongswan.

How do I fix CVE-2026-78123?

Upgrade to a fixed version.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2026-78123 being exploited?

There is no known exploitation of CVE-2026-78123 in the wild and no public exploit code.

Sources

Also known as AZL-100037, DEBIAN-CVE-2026-78123, GHSA-m7ff-3hm8-6qxh, MINI-85wq-4m7f-jm9h, UBUNTU-CVE-2026-78123.