Security readout for executives and security teams
Plain-English summary
This flaw lets a logged-in, low-privileged local user on affected FortiWAN systems run operating-system commands through the CLI and potentially become root. Business risk is concentrated where untrusted or loosely controlled users can access the appliance CLI.
Executive priority
Treat as high priority for affected FortiWAN appliances, especially where multiple operators or third parties have CLI access. It is not described as remote unauthenticated exposure, but root escalation on network infrastructure is operationally serious.
Technical view
CVE-2021-26115 is a CWE-78 OS command injection issue in the FortiWAN CLI. FortiWAN 4.5.7 and below are described as affected, with listed affected branches including 4.5.0 through 4.0.0. The attack is local, low complexity, requires low privileges, and can impact confidentiality, integrity, and availability.
Likely exposure
Exposure is likely limited to FortiWAN deployments where users have local authenticated CLI access. Internet exposure is not indicated by the provided CVSS vector or description.
Exploitation context
The CVSS vector indicates local access and low privileges are required. The bundle does not show CISA KEV listing or cited evidence of exploitation in the wild.
Researcher notes
Evidence is limited to the CVE record, Fortinet PSIRT reference, and supplied CVSS data. The bundle does not provide patch version details, exploit artifacts, or active exploitation evidence. Avoid assuming broader Fortinet product impact.
Mitigation direction
- Review Fortinet PSIRT FG-IR-21-069 for official remediation guidance.
- Identify and prioritize FortiWAN systems running 4.5.7 or below.
- Restrict CLI access to trusted administrative users only.
- Remove unnecessary local accounts and reduce appliance privileges.
- Monitor FortiWAN administrative activity for unexpected privilege changes.
Validation and detection
- Inventory FortiWAN appliance versions across all environments.
- Confirm whether any appliance is version 4.5.7 or below.
- Review user accounts with CLI access on affected appliances.
- Check administrative logs for suspicious local command or privilege activity.
- Document compensating controls if vendor remediation is pending.
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-78: Command execution behavior lookup
Command injection weaknesses can lead defenders to review execution techniques and command interpreter telemetry. 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-26115 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
- High
- CVSS
- 7.6 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:X/RC:C
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:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:X/RC:C1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.6HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:X/RC:C
Source materials
- CVE List V5 sourceCVE List V5
- https://fortiguard.fortinet.com/psirt/FG-IR-21-069CVE reference
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.