Security readout for executives and security teams
Plain-English summary
CVE-2026-1521 can let a remote attacker crash or disrupt the Open5GS SGWC component, causing denial of service. It affects Open5GS versions 2.7.0 through 2.7.6. Public exploit information is referenced, but the provided sources do not show confirmed active exploitation.
Executive priority
Treat as a near-term availability risk for environments using Open5GS. Prioritize patching where SGWC supports production or customer-impacting mobile core services, especially if reachable from less-trusted networks.
Technical view
The flaw is in sgwc_s5c_handle_bearer_resource_failure_indication in src/sgwc/s5c-handler.c. VulDB describes remote manipulation leading to denial of service, mapped to CWE-404. CVSS v4.0 is 6.9 with network attack vector, low complexity, no privileges, and no user interaction.
Likely exposure
Organizations running Open5GS 2.7.0 through 2.7.6 with the SGWC component reachable over relevant network paths are potentially exposed. Exposure is higher where telecom core lab, private mobile network, or production packet-core interfaces are accessible beyond trusted peers.
Exploitation context
Sources state the exploit has been publicly released and may be used for attacks. The CVE is not marked KEV in the provided bundle, and no cited source confirms active exploitation in the wild. The expected impact is service disruption rather than data theft or code execution.
Researcher notes
The public record identifies affected versions, function, file path, CVSS vector, CWE-404, and a named patch commit. Evidence does not establish active exploitation. Fixed release information is not explicit in the provided sources, so validation should focus on commit presence or vendor release notes.
Mitigation direction
- Identify Open5GS deployments and confirm whether SGWC is in use.
- Upgrade or apply upstream patch commit 69b53add90a9479d7960b822fc60601d659c328b.
- Check Open5GS vendor guidance for the first fixed release containing the patch.
- Restrict SGWC-related network reachability to trusted telecom peers and management networks.
- Monitor SGWC service health and crash logs until remediation is complete.
Validation and detection
- Inventory Open5GS versions and flag 2.7.0 through 2.7.6.
- Verify whether patch commit 69b53add90a9479d7960b822fc60601d659c328b is present.
- Review GitHub issue 4268 for vendor discussion and closure context.
- Check logs for unexplained SGWC restarts or denial-of-service symptoms.
- Confirm network controls limit access to relevant Open5GS interfaces.
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-2026-1521 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-343192 | Open5GS SGWC s5c-handler.c denial of serviceCVE reference · vdb-entry, technical-description
- VDB-343192 | CTI Indicators (IOB, IOC, TTP, IOA)CVE reference · signature, permissions-required
- Submit #738370 | Open5GS SGWC v2.7.6 Denial of ServiceCVE reference · third-party-advisory
- https://github.com/open5gs/open5gs/issues/4268CVE reference · issue-tracking, exploit
- https://github.com/open5gs/open5gs/commit/69b53add90a9479d7960b822fc60601d659c328bCVE reference · patch
- https://github.com/open5gs/open5gs/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.