Security Resilience

CVE-2026-44326

Access Control in Free5Gc ≤ 4.2.2

Public PoCAccess Control
Published
27 May 2026
Modified
14 October 2026
Patch / advisory
CVSS Score v3.1 9.4
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H
EPSS Score 0.0053 43th percentile
Risk Priority 69 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-44326 is a critical-severity Missing Authorization (CWE-862) vulnerability in Free5Gc Free5Gc. Its CVSS base score is 9.4 (Critical).

Operationally, ranked at the 43th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-24 (Access Control Decisions) and AC-25 (Reference Monitor) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NEF mounts the 3gpp-traffic-influence API without inbound OAuth2/bearer-token authorization. A network attacker who can reach NEF on the SBI can create, read, patch, and delete traffic-influence…

more

subscriptions either with no Authorization header at all, or with a forged bearer token (e.g. Authorization: Bearer not-a-real-token). This includes creating AnyUeInd=true subscriptions intended to affect group / any-UE traffic steering. The route group is also reachable even when the running config's ServiceList does not declare it, so operators who think they disabled the service via config are still exposed. This vulnerability is fixed in 4.2.2.

CWE(s)

Related Threats

CVEs Like This One

CVE-2024-1686Shared CWE-862
CVE-2021-45467Shared CWE-862
CVE-2024-11926Shared CWE-862
CVE-2024-32146Shared CWE-862
CVE-2025-31618Shared CWE-862
CVE-2023-49003Shared CWE-862
CVE-2024-24704Shared CWE-862
CVE-2024-13231Shared CWE-862
CVE-2023-33477Shared CWE-862
CVE-2024-0619Shared CWE-862

Affected Assets

free5gc
free5gc
≤ 4.2.2

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

AC-3 directly requires enforcement of authorization decisions on every access request, structurally eliminating missing authorization checks.

AC-24 mandates that access control decisions are applied to each request, preventing bypass of authorization logic.

AC-25 requires a tamperproof, always-invoked reference monitor that ensures authorization checks cannot be omitted.

AC-6 reduces the set of actions reachable without proper authorization, limiting blast radius of missing checks.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

blocks

Requiring formal authorization of every access request before rights are granted ensures that checks for required permissions are performed, preventing missing authorization checks from being introduced.

blocks

A.5.18's provisioning, review, revocation and activation steps (incl. owner approval, SoD, timely removal on role/termination change) directly stop exploitation of missing authorization checks by ensuring no actor receives or retains rights to resources they should not access; the bounded remainder is that it cannot stop missing-authorization defects inside the enforcement mechanism itself once rights have been granted (e.g. flawed code that ignores the rights table).

finds

By requiring competent outsiders to verify that every function enforces the need-to-know principle, the control lowers the likelihood that missing authorization checks persist undetected.

blocks

A.5.8 integrates risk assessment, requirements elicitation and governance into the project lifecycle so that authorization needs can be identified and specified; it does not itself perform or enforce authorization checks, so the missing-authorization weakness can still be present and exploitable.

blocks

Security checkpoints and explicit authorization requirements in the design phase ensure that every sensitive function is paired with an access-control check, reducing missing-authorization defects.

blocks

A.8.27 mandates security-by-design principles (least privilege, default deny, security architecture integration, zero-trust never-trust/always-verify, dynamic access control) plus design reviews that directly specify and enforce authorization checks before access; this stops most missing-authorization cases from being exploitable, with a bounded remainder in non-architectural or legacy components where the principles were documented but not fully applied.

Hardening callouts derived

DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.

  • No fine-grained STIG row for CWE-862, a class-level weakness, and none of its children carries one either.

References