Security readout for executives and security teams
Plain-English summary
FortiMail had weaknesses in how some versions protected session cookies. If an attacker already obtains a cookie, they may be able to read or modify its contents and escalate privileges. This is not described as a simple unauthenticated takeover.
Executive priority
Treat as a high-priority FortiMail remediation item, especially for internet-reachable or administrator-facing deployments. The dependency on cookie possession lowers immediate mass-exploitation likelihood, but privilege escalation on email security infrastructure is business-significant.
Technical view
CVE-2021-26095 affects FortiMail 6.4.0-6.4.4 and 6.2.0-6.2.6. The issue combines cryptographic weaknesses in session management, including cookie encryption construction, enabling possible session content disclosure, alteration, or forgery after cookie possession.
Likely exposure
Organizations running the listed FortiMail versions are exposed. Risk is higher where FortiMail management or user access is reachable by untrusted networks, but the source states the attacker must already possess a cookie.
Exploitation context
The bundle does not show CISA KEV listing or cited active exploitation. Exploitation is described as remote but high-complexity and dependent on prior cookie possession, with potential confidentiality, integrity, and availability impact.
Researcher notes
Evidence is limited to the CVE details and Fortinet advisory reference. Do not assume exploit availability or a specific fixed release from this bundle alone. Validate version exposure and session-management risk, then follow Fortinet’s advisory for exact remediation.
Mitigation direction
- Identify all FortiMail appliances and their exact software versions.
- Check Fortinet advisory FG-IR-21-019 for supported remediation guidance.
- Prioritize moving affected versions out of production according to vendor guidance.
- Restrict FortiMail access to trusted networks while remediation is planned.
- Rotate or invalidate sessions after remediation where operationally feasible.
Validation and detection
- Confirm no FortiMail instance runs 6.4.0-6.4.4 or 6.2.0-6.2.6.
- Review FortiMail logs for unusual session use or privilege changes.
- Check whether management interfaces are exposed beyond trusted networks.
- Verify remediation status against Fortinet advisory FG-IR-21-019.
- Document any compensating controls for appliances awaiting remediation.
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-2021-26095 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
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
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:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H1.65.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://fortiguard.com/advisory/FG-IR-21-019CVE 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.