How severe is CVE-2026-78135?

CVE-2026-78135 has a CVSS 3.x base score of 5.6, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2026-78135 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-78135?

CVE-2026-78135 affects Strongswan. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-78135?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-78135 published?

CVE-2026-78135 was published on 2026-09-11 and last updated on 2026-09-16.

CVE-2026-78135

CVE-2026-78135 is a medium-severity vulnerability in Strongswan with a CVSS 3.x base score of 5.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-841.

Key facts

Severity: Medium (CVSS 3.x base score 5.6)
EPSS exploit prediction: 0% (28th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-841
Affected product: Strongswan
Published: 2026-09-11
Last modified: 2026-09-16

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.

Frequently asked questions

What is CVE-2026-78135?: 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.
How severe is CVE-2026-78135?: CVE-2026-78135 has a CVSS 3.x base score of 5.6, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2026-78135 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-78135?: CVE-2026-78135 affects Strongswan. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-78135?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-78135 published?: CVE-2026-78135 was published on 2026-09-11 and last updated on 2026-09-16.

References

Affected products (1)

cpe:2.3:a:strongswan:strongswan:*:*:*:*:*:*:*:*

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