What is CVE-2026-78133?

CVE-2026-78133 is a high-severity vulnerability in Strongswan, classified under Use After Free. CVSS score: 7.5/10. Published 2026-09-11.

How severe is CVE-2026-78133?

High severity. CVSS v3 base score is 7.5 out of 10.

Use After Free in Strongswan

CVE-2026-78133

libcharon in strongSwan 6.0.0 through 6.0.7 has a use-after-free in IKEv2 rekeying collision handling.

Vulnerability class: Use-After-Free

Published 2026-09-11 · last modified 2026-09-14.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.005 (40.0th percentile), scored 2026-10-26.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 40th percentile — 40.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.000

Affected products

Strongswan

Weakness classification (CWE)

CWE-416 — Use After Free

References

github.com/strongswan/strongswan/releases/tag/6.1.0 (Patch, Release Notes, Vendor Advisory)
www.strongswan.org/blog/2026/09/07/strongswan-vulnerability-(cve-2026-78133).ht… (Mitigation, Vendor Advisory)

Frequently asked questions

What is CVE-2026-78133?: CVE-2026-78133 is a high-severity vulnerability in Strongswan, classified under Use After Free. CVSS score: 7.5/10. Published 2026-09-11.
How severe is CVE-2026-78133?: High severity. CVSS v3 base score is 7.5 out of 10.