Security readout for executives and security teams
Plain-English summary
CVE-2026-22153 is a high-severity Fortinet FortiOS authentication bypass affecting versions 7.6.0 through 7.6.4. In specific LDAP configurations, an unauthenticated network attacker may bypass LDAP authentication for Agentless VPN or FSSO policy. Organizations using these features should prioritize review, but exposure depends on configuration.
Executive priority
Treat as a priority for Fortinet environments using LDAP-backed VPN or FSSO controls. The impact could be serious if exploitable in your configuration, but current evidence does not show active exploitation. Assign urgent validation and remediation planning rather than emergency response unless exposure is confirmed.
Technical view
The issue is CWE-305, Authentication Bypass by Primary Weakness, in FortiOS 7.6.0-7.6.4. The CVSS 3.1 score is 7.5 with network attack vector, no privileges, no user interaction, and high confidentiality, integrity, and availability impact. Attack complexity is high and requires a specific remote LDAP server configuration.
Likely exposure
Likely exposed systems are FortiOS 7.6.0 through 7.6.4 deployments using Agentless VPN or FSSO policy with LDAP authentication. Systems not in the 7.6 affected range, or not using the relevant LDAP-backed features, are less likely to be affected based on the provided sources.
Exploitation context
The sources do not indicate CISA KEV listing or active exploitation. Exploitation is described as unauthenticated and network-accessible, but high complexity because it depends on a specific LDAP server configuration. No public exploit details are provided in the source bundle.
Researcher notes
Key unknown is the exact LDAP server configuration required for bypass. The CVSS vector indicates high attack complexity and official remediation availability, but the provided bundle does not name fixed versions. Avoid assuming exploitability across all FortiOS 7.6 deployments; validate feature usage and configuration first.
Mitigation direction
- Identify FortiOS 7.6.0 through 7.6.4 devices.
- Check whether Agentless VPN or FSSO policy uses LDAP authentication.
- Review Fortinet PSIRT FG-IR-25-1052 for official remediation guidance.
- Apply vendor-recommended updates or mitigations when confirmed.
- Restrict management and VPN exposure where operationally feasible.
Validation and detection
- Inventory FortiOS versions across firewalls and VPN gateways.
- Confirm whether affected LDAP-backed features are enabled.
- Compare device versions against Fortinet PSIRT affected versions.
- Review authentication logs for unusual LDAP or VPN access patterns.
- Track Fortinet advisory updates for fixed-version details.
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-305: 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 lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-22153 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:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/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:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C2.25.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C
Source materials
- CVE List V5 sourceCVE List V5
- https://fortiguard.fortinet.com/psirt/FG-IR-25-1052CVE 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.
Authentication Bypass by Primary Weakness
Authentication Bypass by Primary Weakness represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.