Security readout for executives and security teams
Plain-English summary
This flaw can let an unauthenticated attacker bypass FortiCloud SSO login on affected Fortinet products using a crafted SAML response. Because Fortinet devices often protect network access, successful abuse could create a direct path to high-impact compromise. CISA KEV and Arctic Wolf reporting support treating this as actively exploited.
Executive priority
Treat as urgent. This is a critical authentication-bypass issue in security infrastructure with KEV status and reported malicious SSO activity. Confirm exposure and remediate affected systems before routine patch cycles.
Technical view
CVE-2025-59718 is a CWE-347 improper cryptographic signature verification issue affecting FortiOS, FortiProxy, and FortiSwitchManager version ranges listed by the CVE. The attack vector is network-accessible, low complexity, unauthenticated, and requires no user interaction. The CVSS 3.1 score is 9.1 with high confidentiality, integrity, and availability impact.
Likely exposure
Organizations using FortiCloud SSO login with affected FortiOS 7.0-7.6, FortiProxy 7.0-7.6, or FortiSwitchManager 7.0-7.2 ranges are the likely exposure group. Internet-reachable management or authentication paths increase urgency.
Exploitation context
The source bundle marks this CVE as CISA KEV, and Arctic Wolf reports malicious SSO logins following disclosure. That is enough evidence to treat exploitation as active, but the bundle does not provide exploit mechanics or complete incident scope.
Researcher notes
Evidence supports active exploitation, but the prompt bundle lacks exact fixed-version details and detailed indicators. Avoid assuming all deployments are exploitable; validate product, version, SSO configuration, and exposure. Use Fortinet, CISA KEV, and Arctic Wolf sources for follow-up.
Mitigation direction
- Check Fortinet FG-IR-25-647 for official fixed versions and upgrade guidance.
- Prioritize affected internet-reachable Fortinet management and SSO endpoints.
- Review whether FortiCloud SSO is enabled and restrict exposure where possible.
- Monitor Fortinet and identity logs for suspicious SSO authentication events.
- Follow CISA KEV remediation timelines where applicable.
Validation and detection
- Inventory FortiOS, FortiProxy, and FortiSwitchManager versions against listed affected ranges.
- Confirm whether FortiCloud SSO or SAML-based login is enabled.
- Identify any externally reachable management or authentication interfaces.
- Review authentication logs for unexpected FortiCloud SSO logins after disclosure.
- Track Fortinet advisory updates for corrected version guidance.
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-347: 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 lookupCVE-2025-59718 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
- Critical
- CVSS
- 9.1 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/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.
CISA KEV status
SSVC decision data
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:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C3.95.9fortinetVulnerability scoring details
Base CVSS 3.1 score
9.1CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- Added to KEVCISA-ADP
CISA Known Exploited Vulnerabilities metadata lists this CVE as known exploited.
- ADP timelineCISA-ADP
CVE-2025-59718 added to CISA KEV
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2025-12-16T00:00:00.000Z: CVE-2025-59718 added to CISA KEV
Source materials
- CVE List V5 sourceCVE List V5
- https://fortiguard.fortinet.com/psirt/FG-IR-25-647CVE reference, fortinet
- https://arcticwolf.com/resources/blog/arctic-wolf-observes-malicious-sso-logins-following-disclosure-cve-2025-59718-cve-2025-59719/CVE reference, CISA-ADP · third-party-advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-59718CVE reference, CISA-ADP · government-resource
- https://cert-portal.siemens.com/productcert/html/ssa-864900.htmlCVE reference, siemens-SADP
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.
Improper Verification of Cryptographic Signature
Improper Verification of Cryptographic Signature represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.