CVE-2026-42083
CVE-2026-42083 is a high-severity vulnerability in Free5gc with a CVSS 3.x base score of 8.2. 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-862.
Key facts
- Severity: High (CVSS 3.x base score 8.2)
- EPSS exploit prediction: 0% (24th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-32555
- Weakness: CWE-862
- Affected product: Free5gc
- Published:
- Last modified:
Description
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, PCF Npcf_SMPolicyControl missing authentication middleware allows unauthenticated access to SM policy handlers and disclosure of subscriber SUPI. In NewServer(), the smPolicyGroup route group is created and routes are applied without attaching the router authorization middleware. In contrast, other PCF service groups such as Npcf_PolicyAuthorization do attach RouterAuthorizationCheck before route registration. Because the middleware is missing, requests to the /npcf-smpolicycontrol/v1/sm-policies, /npcf-smpolicycontrol/v1/sm-policies/{smPolicyId}, /npcf-smpolicycontrol/v1/sm-policies/{smPolicyId}/update, and /npcf-smpolicycontrol/v1/sm-policies/{smPolicyId}/delete endpoints can reach business logic even when no valid OAuth token is provided. This vulnerability is fixed in 4.2.2.
Frequently asked questions
- What is CVE-2026-42083?
- free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, PCF Npcf_SMPolicyControl missing authentication middleware allows unauthenticated access to SM policy handlers and disclosure of subscriber SUPI. In NewServer(), the smPolicyGroup route group is created and routes are applied without attaching the router authorization middleware. In contrast, other PCF service groups such as Npcf_PolicyAuthorization do attach RouterAuthorizationCheck before route registration. Because the middleware is missing, requests to the /npcf-smpolicycontrol/v1/sm-policies, /npcf-smpolicycontrol/v1/sm-policies/{smPolicyId}, /npcf-smpolicycontrol/v1/sm-policies/{smPolicyId}/update, and /npcf-smpolicycontrol/v1/sm-policies/{smPolicyId}/delete endpoints can reach business logic even when no valid OAuth token is provided. This vulnerability is fixed in 4.2.2.
- How severe is CVE-2026-42083?
- CVE-2026-42083 has a CVSS 3.x base score of 8.2, 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 low, and availability none.
- Is CVE-2026-42083 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-2026-42083?
- CVE-2026-42083 affects Free5gc. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-42083?
- 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-2026-42083 have an EU (EUVD) identifier?
- Yes. CVE-2026-42083 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-32555.
- When was CVE-2026-42083 published?
- CVE-2026-42083 was published on 2026-05-27 and last updated on 2026-06-17.
References
- https://github.com/free5gc/free5gc/issues/844
- https://github.com/free5gc/free5gc/security/advisories/GHSA-6rgm-gr97-x3j5
- https://github.com/free5gc/pcf/commit/8c4d457cdf58bb239ee30e88c56b370b22073964
- https://github.com/free5gc/pcf/pull/63
Affected products (1)
- cpe:2.3:a:free5gc:free5gc:*:*:*:*:*:*:*:*
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