How severe is CVE-2026-42459?

CVE-2026-42459 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2026-42459 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-42459?

CVE-2026-42459 affects Free5gc. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-42459?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-42459 have an EU (EUVD) identifier?

Yes. CVE-2026-42459 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-32554.

When was CVE-2026-42459 published?

CVE-2026-42459 was published on 2026-05-27 and last updated on 2026-06-17.

CVE-2026-42459

CVE-2026-42459 is a high-severity vulnerability in Free5gc with a CVSS 3.x base score of 7.5. 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-20.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 7.7
EPSS exploit prediction: 0% (24th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-32554
Weakness: CWE-20
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 free5GC UDM component fails to validate the supi path parameter in six GET handlers of the nudm-sdm (Subscriber Data Management) service. An unauthenticated attacker can inject control characters into the SUPI parameter, causing UDM to forward a malformed request to UDR and return a 500 Internal Server Error response that exposes internal infrastructure details. This vulnerability is fixed in 4.2.2.

Frequently asked questions

What is CVE-2026-42459?: free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, the free5GC UDM component fails to validate the supi path parameter in six GET handlers of the nudm-sdm (Subscriber Data Management) service. An unauthenticated attacker can inject control characters into the SUPI parameter, causing UDM to forward a malformed request to UDR and return a 500 Internal Server Error response that exposes internal infrastructure details. This vulnerability is fixed in 4.2.2.
How severe is CVE-2026-42459?: CVE-2026-42459 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-42459 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-42459?: CVE-2026-42459 affects Free5gc. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-42459?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-42459 have an EU (EUVD) identifier?: Yes. CVE-2026-42459 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-32554.
When was CVE-2026-42459 published?: CVE-2026-42459 was published on 2026-05-27 and last updated on 2026-06-17.

References

https://github.com/free5gc/free5gc/security/advisories/GHSA-585v-hcgf-jhfr

Affected products (1)

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

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