Reference page — cumulative record through Sunday, October 4, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-78135

CVE-2026-78135HIGH

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

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   N   N  U  L  L  L    7.3   .0036   27.8     —

AFFECTED
  Product     Versions  Fixed
  strongSwan  5.9.7 –   —

TIMELINE
  Aug 22  Reserved by mitre
  Sep 11  Published (CNA: mitre)
  Sep 16  RESCORED — CVE-2026-78135 (strongSwan). CVSS 5.6 → 7.3 (NVD).

CWE-841 · CNA: mitre · CVSS v3.1 · 2 references · NVD status: Analyzed

Description

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.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
August 22, 2026	Reserved	Reserved by mitre
September 11, 2026	Published	Published (CNA: mitre)
September 16, 2026	RESCORED	RESCORED — CVE-2026-78135 (strongSwan). CVSS 5.6 → 7.3 (NVD).

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
strongSwan	strongSwan	—	5.9.7	—

Weaknesses

CWE-841

References (2)

https://github.com/strongswan/strongswan/releases/tag/6.1.0 [Release Notes, Vendor Advisory]
https://www.strongswan.org/blog/2026/09/07/strongswan-vulnerability-(cve-2026-78135).html [Vendor Advisory, Mitigation]

Authoritative record: CVE-2026-78135 at cve.org

Vendors: strongswan

Weaknesses: CWE-841

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-78135 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Sunday, October 4, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.