Security readout for executives and security teams
Plain-English summary
FortiWeb versions 6.4.0 and 6.4.1 contain a memory-safety flaw that can let an authenticated attacker run unauthorized code or commands through crafted certificates loaded into the appliance. The impact is high because successful exploitation can compromise confidentiality, integrity, and availability.
Executive priority
Treat this as a high-priority appliance remediation issue if FortiWeb 6.4.0 or 6.4.1 is present. The main business risk is administrative-context compromise of a security control that protects web applications.
Technical view
CVE-2021-41027 is a stack-based buffer overflow in Fortinet FortiWeb 6.4.0 and 6.4.1. The CVSS 3.1 score is 7.3 with local access, low privileges, and user interaction required. The source bundle describes code or command execution via crafted certificates loaded into the device.
Likely exposure
Exposure is most likely in FortiWeb appliances running 6.4.0 or 6.4.1 where authenticated users can load certificates. The provided CVSS vector indicates local access and user interaction, so the supplied sources do not support treating this as an unauthenticated public-facing attack.
Exploitation context
The bundle marks CISA KEV status as false and provides no cited evidence of active exploitation. Exploitability is noted as proof-of-concept level in the CVSS vector, but no exploit details are provided here and none should be inferred.
Researcher notes
The provided evidence is narrow: affected versions, vulnerability class, attack preconditions, and impact are clear, but fixed versions and detailed mitigations are not included in the bundle. Avoid assuming broader FortiWeb version exposure without vendor confirmation.
Mitigation direction
- Inventory FortiWeb appliances and identify any running versions 6.4.0 or 6.4.1.
- Check Fortinet advisory FG-IR-21-134 for vendor-approved fixed versions and upgrade guidance.
- Limit certificate-loading permissions to trusted administrative accounts only.
- Review recent certificate import activity and administrative changes on affected appliances.
- Monitor FortiWeb logs for unexpected command execution or abnormal appliance behavior.
Validation and detection
- Confirm FortiWeb version numbers from appliance management interfaces or asset inventory.
- Verify whether certificate-management access is restricted to approved administrators.
- Review change logs for certificate uploads during the exposure period.
- Check whether remediation followed Fortinet advisory FG-IR-21-134.
- Document any affected appliances that remain on 6.4.0 or 6.4.1.
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.
CVE-2021-41027 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
- 7.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/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:R/S:U/C:H/I:H/A:H/E:P/RL:X/RC:C1.35.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.3HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/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-21-134CVE 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.