CVE-2026-78135

MEDIUM

5.6

CVSS v3

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.

CWE-841

How to fix

Remediation Available

strongswanDebian

Fixed in:6.0.1-6+deb13u7CVE-2026-78135

Fixed in:6.1.0-1CVE-2026-78135

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityHigh

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityLow

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L

Exploit Intelligence

0.36%probability of exploitation in 30 days

30thpercentile

Low risk: more likely to be exploited than 30% of all known CVEs.

References

Vendor Advisory2

Related Vulnerabilities

Other CWE-841 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2022-1667	High	7.5	1.3%	-	Fix
CVE-2023-4181	Medium	5.4	1.1%	-	-
CVE-2022-2105	Critical	9.4	1.1%	-	Fix
CVE-2022-2102	Critical	9.4	0.9%	-	Fix
CVE-2024-51738	High	8.1	0.6%	-	Fix
CVE-2025-55332	High	6.1	0.6%	-	Fix

Common questions

How do I fix CVE-2026-78135?

Upgrade strongswan on debian 13 to 6.0.1-6+deb13u7 or later.

Is CVE-2026-78135 being actively exploited?

Not that we know of. CVE-2026-78135 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.36% is the estimated probability that it will be exploited in the next 30 days. That is higher than 30% of all scored CVEs.

How severe is CVE-2026-78135?

CVE-2026-78135 has a CVSS v3 base score of 5.6, rated moderate. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-78135 affect?

Published advisories record a fix for strongswan (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

Embed a live status badge for CVE-2026-78135

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-16.