Vulnerability · Published Sep 11, 2026 · Assigned by mitre
CVE-2026-78135
Medium 5.6
In plain English
A medium-severity security flaw in strongSwan from strongSwan. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)5.6Medium
Exploit odds (30 days)0.4%top 63.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | strongswan | 5.9.8-5+deb12u6 | DEBIAN-CVE-2026-78135 |
| Debian:13 | strongswan | 6.0.1-6+deb13u7 | DEBIAN-CVE-2026-78135 |
| Debian:14 | strongswan | 6.1.0-1 | DEBIAN-CVE-2026-78135 |
| Ubuntu:22.04:LTS | strongswan | 5.9.5-2ubuntu2.8 | UBUNTU-CVE-2026-78135 |
| Ubuntu:22.04:LTS | strongswan | 5.9.5-2ubuntu2.8 | USN-8789-1 |
| Ubuntu:24.04:LTS | strongswan | 5.9.13-2ubuntu4.24.04.5 | USN-8789-1 |
| Ubuntu:24.04:LTS | strongswan | 5.9.13-2ubuntu4.24.04.5 | UBUNTU-CVE-2026-78135 |
| Ubuntu:26.04:LTS | strongswan | 6.0.4-1ubuntu3.2 | USN-8789-1 |
| Ubuntu:26.04:LTS | strongswan | 6.0.4-1ubuntu3.2 | UBUNTU-CVE-2026-78135 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| strongSwan | strongSwan | 5.9.7 – before 6.1.0 |
Weakness: CWE-841 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L