CVE-2026-1684
Published: 30 January 2026
Summary
CVE-2026-1684 is a medium-severity Improper Resource Shutdown or Release (CWE-404) vulnerability in Free5Gc Free5Gc. Its CVSS base score is 6.9 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked in the top 41.9% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SC-5 (Denial-of-service Protection) and SI-10 (Information Input Validation).
Deeper analysis
CVE-2026-1684 is a denial-of-service vulnerability in Free5GC SMF versions up to 4.1.0. The issue affects the HandleReports function in the file /internal/context/pfcp_reports.go within the PFCP UDP Endpoint component. Published on 2026-01-30, it has a CVSS v3.1 base score of 5.3 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L) and is associated with CWE-404.
The vulnerability can be exploited remotely by unauthenticated attackers with network access and low complexity requirements, requiring no user interaction. Successful exploitation leads to a denial of service, impacting availability with low severity due to unchanged scope and no effects on confidentiality or integrity.
Mitigation involves applying an available patch, as recommended in the vulnerability description. Relevant resources include the GitHub issue at https://github.com/free5gc/free5gc/issues/806, the SMF repository at https://github.com/free5gc/smf/, and the pull request at https://github.com/free5gc/smf/pull/188, along with details from VulDB at https://vuldb.com/?ctiid.343477 and https://vuldb.com/?id.343477.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-5028
Vulnerability details
A vulnerability was found in Free5GC SMF up to 4.1.0. Affected by this issue is the function HandleReports of the file /internal/context/pfcp_reports.go of the component PFCP UDP Endpoint. The manipulation results in denial of service. The attack can be executed…
more
remotely. It is advisable to implement a patch to correct this issue.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The CVE describes remote exploitation of a software flaw in a network-exposed PFCP UDP endpoint (HandleReports) that directly results in application/service unavailability, matching T1499.004 Application or System Exploitation for Endpoint DoS.
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Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly requires mechanisms to protect against or limit the effects of DoS attacks targeting the PFCP UDP endpoint.
Requires validation of inputs to the HandleReports function so that malformed PFCP reports cannot trigger the DoS condition.
Mandates timely installation of the available patch that corrects the improper resource handling flaw in pfcp_reports.go.