Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-40246 is a high-severity Improper Authorization (CWE-285) vulnerability in Free5Gc Free5Gc. Its CVSS base score is 8.7 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Executable Installer File Permissions Weakness (T1574.005); ranked at the 32th 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.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-40246 affects the UDR service in free5GC, an open-source implementation of the 5G core network, in versions 1.4.2 and prior. The vulnerability resides in the handler for deleting Traffic Influence Subscriptions, which validates whether the influenceId path segment matches subs-to-notify. Upon validation failure, it sends an HTTP 404 Not Found response but fails to halt execution, allowing the subscription deletion to proceed regardless. This flaw, classified under CWE-285 (Improper Authorization), carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N), indicating high integrity impact potential.
An unauthenticated attacker with network access to the 5G Service Based Interface can exploit this by sending a DELETE request with an arbitrary influenceId value in the path segment. The API will misleadingly return a 404 response, masking the successful deletion of any target Traffic Influence Subscription. This enables disruption of policy and charging control mechanisms reliant on these subscriptions within the 5G core.
The GitHub security advisory (GHSA-g9cw-qwhf-24jp) details the issue but notes no patched version was available at the time of publication on 2026-04-16. Security practitioners should monitor the free5GC repository for updates, restrict Service Based Interface exposure, and implement network-level access controls until a fix emerges.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-23304
Vulnerability Data
free5GC is an open-source implementation of the 5G core network. In versions 1.4.2 and below of the UDR service, the handler for deleting Traffic Influence Subscriptions checks whether the influenceId path segment equals subs-to-notify, but does not return after sending…
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the HTTP 404 response when validation fails. Execution continues and the subscription is deleted regardless. An unauthenticated attacker with access to the 5G Service Based Interface can delete arbitrary Traffic Influence Subscriptions by supplying any value for the influenceId path segment, while the API misleadingly returns a 404 Not Found response. A patched version was not available at the time of publication.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 6 hardening rules · 3 OS baselines
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Mitigating Controls (NIST 800-53 r5) AI
Mandates that access-control decisions are made and applied to each request before access occurs.
Requires a tamperproof, always-invoked reference monitor that performs authorization checks.
Directly requires enforcement of approved authorizations for every access request, stopping improper or missing checks.
Limits granted privileges so that even a bypassed check affects fewer resources.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
PR.AA-05 mostly prevents CWE-285 via enforced policy, reviews, and least-privilege authorization decisions, yet CWE-285 remains only partially prevented because code-level check omissions or errors can still occur outside that single control.
Secure SDLC practices catch and eliminate most authorization defects before release, yet a single broad outcome cannot address every design, role, and runtime facet of CWE-285.
PR.AA-01 supplies managed identities and access-request workflows that can support downstream authorization decisions, yet does nothing to enforce or verify authorization checks inside a product, leaving CWE-285 fully unaddressed by this control alone.
Network segmentation/zero-trust limits external reachability (partial prevention of exploitation) but leaves application-level authorization logic untouched, so the CWE remains fully introducible and only one facet of its risk is addressed.
PR.PS-05 blocks unauthorized binaries/DNS while CWE-285 is an in-product authorization-check defect, so the control neither prevents the weakness nor removes any of its risk.
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.
By requiring documented authorization rules and periodic policy reviews, the control makes it less likely that authorization decisions will be omitted or implemented inconsistently across applications.
Mapping access rights to information classification and business requirements forces correct enforcement of authorization decisions, blocking the incorrect authorization weakness at the policy and implementation stage.
Independent reviewers evaluate whether authorization logic matches policy, thereby reducing the window in which incorrect or missing authorization checks remain in production.
By requiring managers to verify that authorization decisions match policy and to remediate deviations, the control limits the persistence of incorrect or missing authorization checks.
Requiring authorization processes and privilege assignments to be specified during project initiation prevents downstream components from receiving overly broad or incorrect rights that would allow unauthorized actions.
By requiring gateways to evaluate every cross-domain request against security requirements, the control stops requests from bypassing intended authorization checks.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (higher-evidence rows only; rows rated `none` are excluded).
Oracle Linux 8 (2 rules)
- V-252656 The OL 8 operating system must not be configured to bypass password requirements for privilege escalation. prevents CWE-285
- V-248581 OL 8 must require users to provide a password for privilege escalation. prevents CWE-285
RHEL 7 (3 rules)
- V-204429 The Red Hat Enterprise Linux operating system must be configured so that users must provide a password for privilege escalation. prevents CWE-285
- V-204430 The Red Hat Enterprise Linux operating system must be configured so that users must re-authenticate for privilege escalation. prevents CWE-285
- V-251704 The Red Hat Enterprise Linux operating system must not be configured to bypass password requirements for privilege escalation. prevents CWE-285
RHEL 8 (1 rule)
- V-251712 The RHEL 8 operating system must not be configured to bypass password requirements for privilege escalation. prevents CWE-285