Security readout for executives and security teams
Plain-English summary
CVE-2026-1683 can let a remote, unauthenticated actor crash or disrupt the Free5GC SMF component by abusing PFCP session report handling. The reported impact is denial of service, not data theft or code execution. Public exploit information exists, but the provided sources do not show confirmed active exploitation.
Executive priority
Handle this as a near-term availability issue for affected Free5GC deployments. It is not described as data compromise, but disruption to 5G core session management can affect service reliability. Patch planning should be prioritized where Free5GC supports production-like, customer-facing, or critical test environments.
Technical view
The flaw affects Free5GC SMF versions 4.0 and 4.1.0 in HandlePfcpSessionReportRequest within internal/pfcp/handler/handler.go. VulDB maps it to CWE-404 and CVSS 4.0 score 6.9: network attack vector, low complexity, no privileges, no user interaction, and low availability impact. A patch is referenced in free5GC SMF pull request 188.
Likely exposure
Exposure is likely limited to organizations running Free5GC SMF 4.0 or 4.1.0, especially telecom labs, private 5G environments, research deployments, and test cores. Risk increases if PFCP traffic can reach SMF from untrusted or poorly segmented networks.
Exploitation context
The source bundle states remote exploitation is possible and that exploit details have been publicly disclosed. CISA KEV is false, and no provided source confirms in-the-wild exploitation. Treat this as a practical denial-of-service risk rather than a confirmed active campaign.
Researcher notes
Evidence is strongest for affected component, versions, remote DoS impact, public disclosure, and patch reference. The provided sources do not establish a fixed release version, active exploitation, or broader product impact beyond Free5GC SMF 4.0 and 4.1.0. Avoid assuming impact to other free5GC components without vendor confirmation.
Mitigation direction
- Identify Free5GC SMF 4.0 and 4.1.0 deployments.
- Review free5GC SMF pull request 188 and vendor guidance.
- Deploy the referenced patch after testing in your environment.
- Prioritize systems where PFCP is reachable from untrusted networks.
- Monitor vendor issue 804 for status and remediation updates.
Validation and detection
- Confirm deployed Free5GC SMF version numbers.
- Determine whether SMF PFCP interfaces are reachable by untrusted sources.
- Check change management for application of PR 188 or successor fixes.
- Review monitoring for unexplained SMF crashes or service restarts.
- Track CVE and vendor issue updates for revised affected versions.
Public sources used
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-2026-1683 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:P
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:P——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:P
Source materials
- CVE List V5 sourceCVE List V5
- VDB-343476 | Free5GC SMF PFCP handler.go HandlePfcpSessionReportRequest denial of serviceCVE reference · vdb-entry, technical-description
- VDB-343476 | CTI Indicators (IOB, IOC, TTP, IOA)CVE reference · signature, permissions-required
- Submit #739653 | free5gc SMF v4.1.0 Denial of ServiceCVE reference · third-party-advisory
- Submit #739654 | free5gc SMF v4.1.0 Denial of Service (Duplicate)CVE reference · third-party-advisory
- https://github.com/free5gc/free5gc/issues/804CVE reference · issue-tracking, exploit
- 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.