How severe is CVE-2026-42081?

CVE-2026-42081 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability low.

Is CVE-2026-42081 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-42081?

CVE-2026-42081 affects Free5gc. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-42081?

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

Does CVE-2026-42081 have an EU (EUVD) identifier?

Yes. CVE-2026-42081 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-32557.

When was CVE-2026-42081 published?

CVE-2026-42081 was published on 2026-05-27 and last updated on 2026-06-17.

CVE-2026-42081

CVE-2026-42081 is a medium-severity vulnerability in Free5gc with a CVSS 3.x base score of 6.1. 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-358.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
EPSS exploit prediction: 0% (18th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-32557
Weakness: CWE-358
Affected product: Free5gc
Published: 2026-05-27
Last modified: 2026-06-17

Description

free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, the AMF in Free5GC does not verify the UE Security Capabilities received in NGAP PathSwitchRequest messages against its locally stored values, as mandated by 3GPP TS 33.501 §6.7.3.1. A malicious gNB can overwrite the AMF's stored UE security capabilities with arbitrary values, which are then propagated in PathSwitchRequest Acknowledge messages and subsequent Handover Request messages. This leads to persistent handover denial-of-service for affected UEs. This vulnerability is fixed in 4.2.2.

Frequently asked questions

What is CVE-2026-42081?: free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, the AMF in Free5GC does not verify the UE Security Capabilities received in NGAP PathSwitchRequest messages against its locally stored values, as mandated by 3GPP TS 33.501 §6.7.3.1. A malicious gNB can overwrite the AMF's stored UE security capabilities with arbitrary values, which are then propagated in PathSwitchRequest Acknowledge messages and subsequent Handover Request messages. This leads to persistent handover denial-of-service for affected UEs. This vulnerability is fixed in 4.2.2.
How severe is CVE-2026-42081?: CVE-2026-42081 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability low.
Is CVE-2026-42081 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-42081?: CVE-2026-42081 affects Free5gc. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-42081?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-42081 have an EU (EUVD) identifier?: Yes. CVE-2026-42081 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-32557.
When was CVE-2026-42081 published?: CVE-2026-42081 was published on 2026-05-27 and last updated on 2026-06-17.

References

https://github.com/free5gc/free5gc/security/advisories/GHSA-77x9-rf64-92gv

Affected products (1)

cpe:2.3:a:free5gc:free5gc:*:*:*:*:*:*:*:*

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