Security readout for executives and security teams
Plain-English summary
CVE-2021-41016 is a command injection flaw in Fortinet FortiExtender. An attacker with authenticated CLI access could run privileged shell commands, which can expose data, change device behavior, or disrupt service. The source bundle does not show active exploitation or exact fixed versions.
Executive priority
Treat this as high priority where FortiExtender is deployed. The attacker needs authenticated CLI access, but successful exploitation can produce full device compromise impacts across confidentiality, integrity, and availability.
Technical view
The flaw is improper neutralization of special command elements in FortiExtender CLI handling. A low-privileged authenticated attacker can inject special characters into CLI commands to execute privileged shell commands. CVSS 3.1 is 7.8, with local access, low complexity, low privileges, no user interaction, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is limited to Fortinet FortiExtender deployments running 7.0.1 and below, 4.2.3 and below, or 4.1.7 and below, especially where non-admin or broad operator accounts have CLI access.
Exploitation context
The bundle lists KEV as false, so there is no source-grounded evidence of known active exploitation. The CVSS vector includes E:P, indicating proof-of-concept maturity, but the provided sources do not include exploit details.
Researcher notes
The provided affected-products field is incomplete, but the description identifies Fortinet FortiExtender and affected version ranges. The source bundle does not provide fixed versions, exploit detail, or observed exploitation evidence. Avoid assuming internet-wide exposure without local inventory data.
Mitigation direction
- Review Fortinet FG-IR-21-148 for vendor-fixed FortiExtender versions and guidance.
- Upgrade affected FortiExtender devices according to Fortinet guidance.
- Restrict CLI and management access to trusted administrators and management networks.
- Remove unnecessary accounts with FortiExtender CLI access.
- Monitor FortiExtender logs for unusual privileged command activity.
Validation and detection
- Inventory FortiExtender devices and record firmware versions.
- Flag versions 7.0.1 and below, 4.2.3 and below, and 4.1.7 and below.
- Review which users or systems can authenticate to the FortiExtender CLI.
- Check Fortinet advisory FG-IR-21-148 for current remediation guidance.
- Review device logs for suspicious command execution or unexpected configuration changes.
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.
Execution 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-2021-41016 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
- 7.8 (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:P/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:P/RL:X/RC:C1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:C
Source materials
- CVE List V5 sourceCVE List V5
- https://fortiguard.com/advisory/FG-IR-21-148CVE reference · x_refsource_CONFIRM
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.