Security readout for executives and security teams
Plain-English summary
CVE-2026-1684 is a remotely reachable denial-of-service issue in Free5GC SMF. An attacker who can reach the PFCP UDP endpoint may disrupt SMF availability. Business urgency depends on whether Free5GC SMF is deployed in production and whether PFCP is exposed beyond trusted network segments.
Executive priority
Treat as a near-term availability risk for organizations using Free5GC in production or lab environments connected to broader networks. Prioritize inventory and PFCP access restriction first, then patch tracking. Lower priority if Free5GC SMF is not deployed or is isolated in a controlled test environment.
Technical view
The reported flaw affects Free5GC SMF through version 4.1.0, specifically HandleReports in internal/context/pfcp_reports.go for the PFCP UDP endpoint. The CVE describes improper resource management leading to denial of service. CVSS 4.0 score is 6.9, network exploitable, low complexity, no privileges, no user interaction, with low availability impact.
Likely exposure
Exposure is most likely in Free5GC SMF deployments running version 4.0 or 4.1.0 where the PFCP UDP endpoint is reachable by untrusted or weakly trusted networks. Internet exposure is not stated in the sources and should be verified locally.
Exploitation context
The CVE states remote exploitation is possible. CISA KEV status is false in the provided bundle, and no cited source establishes active exploitation. Public references include VulDB entries, GitHub issue tracking, and a Free5GC SMF pull request labeled as a patch.
Researcher notes
Evidence is limited to the CVE/VulDB summary and GitHub references. The bundle identifies the affected function and component but does not provide a fixed release number. Avoid assuming exploit availability or active exploitation. Validate patch state directly from the Free5GC SMF pull request and related issue.
Mitigation direction
- Identify Free5GC SMF deployments and their running versions.
- Restrict PFCP UDP endpoint access to trusted network peers only.
- Review the Free5GC SMF pull request and project guidance for patch status.
- Apply vendor-approved updates or patches when available.
- Monitor SMF availability and PFCP-related errors for abnormal patterns.
Validation and detection
- Confirm whether Free5GC SMF 4.0 or 4.1.0 is present.
- Map network paths that can reach the PFCP UDP endpoint.
- Check whether the referenced Free5GC SMF patch is applied.
- Review release notes or vendor issue updates for a fixed version.
- Verify network controls limit PFCP access to expected peers.
Public sources used
- CVE Program
- CVE List V5
- VDB-343477 | Free5GC SMF PFCP UDP Endpoint pfcp_reports.go HandleReports denial of service
- VDB-343477 | CTI Indicators
- Submit #739655 | free5gc SMF v4.1.0 Denial of Service
- Submit #739656 | free5gc SMF v4.1.0 Denial of Service Duplicate
- Free5GC issue 806
- Free5GC SMF pull request 188
- Free5GC SMF repository
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-404: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-1684 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.9 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X——Primary CVE scoreVulnerability scoring details
Base CVSS 4.0 score
6.9MediumVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X
Source materials
- CVE List V5 sourceCVE List V5
- VDB-343477 | Free5GC SMF PFCP UDP Endpoint pfcp_reports.go HandleReports denial of serviceCVE reference · vdb-entry, technical-description
- VDB-343477 | CTI Indicators (IOB, IOC, TTP, IOA)CVE reference · signature, permissions-required
- Submit #739655 | free5gc SMF v4.1.0 Denial of ServiceCVE reference · third-party-advisory
- Submit #739656 | free5gc SMF v4.1.0 Denial of Service (Duplicate)CVE reference · third-party-advisory
- https://github.com/free5gc/free5gc/issues/806CVE reference · issue-tracking
- https://github.com/free5gc/smf/pull/188CVE reference · issue-tracking, patch
- https://github.com/free5gc/smf/CVE reference · product
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Resource Shutdown or Release
Improper Resource Shutdown or Release represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.