Security readout for executives and security teams
Plain-English summary
A flaw in Fortinet SSL-VPN software can let an unauthenticated remote attacker take control of a vulnerable device. Because these gateways often face the internet, compromise could expose network access, sensitive data, and business operations. CISA lists the vulnerability as known exploited.
Executive priority
Treat internet-facing affected appliances as an immediate remediation priority. The combination of unauthenticated remote code execution, critical impact, and confirmed exploitation creates a credible path to network compromise. Require accountable inventory, remediation status, and evidence-based validation rather than assuming upgrades completed successfully.
Technical view
CVE-2023-27997 is a heap-based buffer overflow (CWE-122) in affected FortiOS and FortiProxy SSL-VPN implementations. Crafted network requests may cause arbitrary code or command execution without credentials or user interaction. Its CVSS 3.1 score is 9.2, with high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is greatest where SSL-VPN is enabled and externally reachable on FortiOS 7.2.4, 7.0.11, 6.4.12, 6.0.16 or earlier branch releases, or the specified FortiProxy branches. Exact build applicability should be confirmed against Fortinet's advisory because the bundle's structured affected records are ambiguous.
Exploitation context
CISA's Known Exploited Vulnerabilities catalog supports active exploitation in the wild. The supplied sources do not identify campaigns, targets, exploitation volume, indicators of compromise, or whether any specific deployment has been breached.
Researcher notes
The supplied description gives branch-level affected ranges, but the structured affected entries list selected versions with defaultStatus set to “unaffected.” Do not infer precise applicability from those entries alone. Consult FG-IR-23-097 for authoritative build mappings, remediation releases, workarounds, and detection guidance. No exploit mechanics or indicators are included here.
Mitigation direction
- Inventory FortiOS and FortiProxy appliances, recording exact versions and whether SSL-VPN is enabled.
- Consult Fortinet advisory FG-IR-23-097 and apply its current vendor-recommended upgrade or remediation.
- Reduce or remove public SSL-VPN exposure until remediation, if business operations permit.
- Apply compensating access restrictions where immediate vendor remediation is not operationally possible.
Validation and detection
- Confirm each appliance's exact product, branch, build, and SSL-VPN configuration.
- Determine whether each SSL-VPN interface is reachable from untrusted networks.
- Verify installed builds against Fortinet's current affected and remediated version guidance.
- Review relevant appliance logs using vendor-published indicators if available; this bundle provides none.
- After remediation, confirm the expected build is running and external exposure matches policy.
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-122: 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 lookupExecution 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-2023-27997 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
- 9.2 (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:X/RC:R
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:X/RC:R3.95.9fortinetVulnerability scoring details
Base CVSS 3.1 score
9.2CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:X/RC:R
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.
- Added to KEVCISA-ADP
CISA Known Exploited Vulnerabilities metadata lists this CVE as known exploited.
- ADP timelineCISA-ADP
CVE-2023-27997 added to CISA KEV
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2023-06-13T00:00:00.000Z: CVE-2023-27997 added to CISA KEV
Source materials
- CVE List V5 sourceCVE List V5
- https://fortiguard.com/psirt/FG-IR-23-097CVE reference, fortinet
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-27997CVE reference, CISA-ADP · government-resource
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.
Heap-based Buffer Overflow
Heap-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.