CVE-2023-27997
Confirmed PUBLISHEDA heap-based buffer overflow vulnerability [CWE-122] in FortiOS version 7.2.4 and below, version 7.0.11 and below, version 6.4.12 and below,...
Recommended Action
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
At a Glance
A heap-based buffer overflow vulnerability [CWE-122] in FortiOS version 7.2.4 and below, version 7.0.11 and below, version 6.4.12 and below, version 6.0.16 and below and FortiProxy version 7.2.3 and below, version 7.0.9 and below, version 2.0.12 and below, version 1.2 all versions, version 1.1 all versions SSL-VPN may allow a remote attacker to execute arbitrary code or commands via specifically crafted requests.
- CVE Published
- Jun 13, 2023
- Exploitation Reported
- Jun 13, 2023
- CVSS
- 9.2 Critical
- EPSS
- —
Affected Versions
| Vendor | Product | Version | Status |
|---|---|---|---|
| Fortinet |
FortiOS-6K7K
|
7.0.10 |
Affected |
| Fortinet |
FortiOS-6K7K
|
7.0.5 |
Affected |
| Fortinet |
FortiOS-6K7K
|
6.4.12 |
Affected |
| Fortinet |
FortiOS-6K7K
|
6.4.10 |
Affected |
| Fortinet |
FortiOS-6K7K
|
6.4.8 |
Affected |
| Fortinet |
FortiOS-6K7K
|
6.4.6 |
Affected |
| Fortinet |
FortiOS-6K7K
|
6.4.2 |
Affected |
| Fortinet |
FortiOS-6K7K
|
6.2.9 to <= 6.2.13 |
Affected |
| Fortinet |
FortiOS-6K7K
|
6.2.6 to <= 6.2.7 |
Affected |
| Fortinet |
FortiOS-6K7K
|
6.2.4 |
Affected |
| Fortinet |
FortiOS-6K7K
|
6.0.12 to <= 6.0.16 |
Affected |
| Fortinet |
FortiOS-6K7K
|
6.0.10 |
Affected |
| Fortinet |
FortiProxy
|
7.2.0 to <= 7.2.3 |
Affected |
| Fortinet |
FortiProxy
|
7.0.0 to <= 7.0.9 |
Affected |
| Fortinet |
FortiProxy
|
2.0.0 to <= 2.0.12 |
Affected |
| Fortinet |
FortiProxy
|
1.2.0 to <= 1.2.13 |
Affected |
| Fortinet |
FortiProxy
|
1.1.0 to <= 1.1.6 |
Affected |
| Fortinet |
FortiOS
|
7.2.0 to <= 7.2.4 |
Affected |
| Fortinet |
FortiOS
|
7.0.0 to <= 7.0.11 |
Affected |
| Fortinet |
FortiOS
|
6.4.0 to <= 6.4.12 |
Affected |
| Fortinet |
FortiOS
|
6.2.0 to <= 6.2.13 |
Affected |
| Fortinet |
FortiOS
|
6.0.0 to <= 6.0.16 |
Affected |
CVE References
- https://fortiguard.com/psirt/FG-IR-23-097 fortiguard.com · CVE Record https://fortiguard.com/psirt/FG-IR-23-097
Recommended Actions
- Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
- Check enrichment artifacts for scanner coverage and available PoCs before rolling remediation validation.
- Use the Pro API to automate enrichment, telemetry, and workflow delivery for VM, SOC, and CTI pipelines.
Known Exploited Vulnerability Sources
Catalogues that list this CVE as a known exploited vulnerability.
Per-source evidence links for KEV attestations are available through the KEVIntel Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CISA First | 2023-06-13 00:00 UTC |
No detection artifacts or sensor request patterns are available for this CVE yet.
Check back as sensor telemetry and scanner integrations are updated.
Virtual Patch
Compensating WAF rules to help reduce exposure to this CVE. Rule content and deployable vendor exports are available with KEVIntel Enterprise.
KEVIntel does not currently have a virtual patch for this CVE. When available, KEVIntel virtual patches ship as deployable ModSecurity, Cloudflare, and AWS WAF rules.
Enterprise feature. Virtual patch rule content and deployable vendor exports (ModSecurity, Cloudflare, AWS WAF) are available to KEVIntel Enterprise users.
CVSS Scores
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
Exploitation Status
Exploited in the wild
Recorded 2023-06-13 00:00:00 UTC · CISA
Used in malware
Recorded 2023-06-13 00:00:00 UTC · CISA
Proof of concept available
Recorded 2023-06-16 03:25:19 UTC · GitHub
Weaknesses (CWE)
-
Heap-based Buffer Overflow
Scanner Integrations
| Scanner | Reference | Detected |
|---|---|---|
| Nessus | https://www.tenable.com/plugins/nessus/177116 | Jun 02, 2025 |
Recent Mentions
Tenable Blog · May 14, 2025
Fortinet has observed threat actors exploiting CVE-2025-32756, a critical zero-day arbitrary code execution vulnerability which affects multiple Fortinet products including FortiVoice, FortiMail, FortiNDR, FortiRecorder and FortiCamera.BackgroundOn May 13th, Fortinet published a security advisory (FG-IR-25-254) for CVE-2025-32756, a critical arbitrary code execution vulnerability affecting multiple Fortinet products.CVEDescriptionCVSSv3CVE-2025-32756An arbitrary code execution vulnerability in FortiVoice, FortiMail, FortiNDR, FortiRecorder and FortiCamera9.6AnalysisCVE-2025-32756 is an arbitrary code execution vulnerability affecting multiple Fortinet products including FortiVoice, FortiMail, FortiNDR, FortiRecorder and FortiCamera. A remote unauthenticated attacker can send crafted HTTP requests in order to create a stack-based overflow condition which would allow for the execution of arbitrary code. This vulnerability was discovered by the Fortinet Product Security Team who observed threat activity involving a device running FortiVoice.According to Fortinet, the threat actors operations included scanning the network, erasing system crashlogs and enabling ‘fcgi debugging’ which is used to log authentication attempts, including SSH logins. The ‘fcgi debugging’ option is not enabled by default and the Fortinet advisory recommends reviewing the setting as one possible indicator of compromise (IoC).Historical Exploitation of Fortinet DevicesFortinet vulnerabilities have historically been common targets for cyber attackers, and CVE-2025-32756 is the eighteenth Fortinet vulnerability to be added to the Cybersecurity and Infrastructure Security Agency’s (CISA) Known Exploited Vulnerabilities (KEV) list.CVEDescriptionPatchedTenable BlogCVE-2024-55591Fortinet Authentication Bypass in FortiOS and FortiProxyJanuary 2025CVE-2024-55591: Fortinet Authentication Bypass Zero-Day Vulnerability Exploited in the WildCVE-2024-21762Fortinet FortiOS Out-of-bound Write Vulnerability...
Potential Proof of Concepts
These PoCs are unverified and could contain malware. Use at your own risk.
github · Created 2023-10-12 17:50:38 UTC · 9 stars
github · Created 2023-06-22 14:16:44 UTC · 1 stars
github · Created 2023-06-16 20:15:36 UTC · 133 stars
Safely detect whether a FortiGate SSL VPN instance is vulnerable to CVE-2023-27997 based on response timing
github · Created 2023-06-16 03:25:19 UTC · 27 stars
POC FortiOS SSL-VPN buffer overflow vulnerability
Timeline
Key exploitation, disclosure, scanner coverage, and KEV attestation events for this CVE.
-
09:26 UTC about 1 year ago09:26 UTC · about 1 year ago
Nessus plugin available
Scanner coverage available
-
03:25 UTC about 3 years ago03:25 UTC · about 3 years ago
Public PoC available
Public proof-of-concept code published
-
08:41 UTC about 3 years ago08:41 UTC · about 3 years ago
CVE published
Vulnerability disclosed publicly
-
00:00 UTC about 3 years ago00:00 UTC · about 3 years ago
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
00:00 UTC about 3 years ago00:00 UTC · about 3 years ago
First public exploitation report
Exploit observed in malware
-
10:09 UTC over 3 years ago10:09 UTC · over 3 years ago
CVE ID reserved
Identifier reserved by the CNA
Automate This Intelligence with the Pro API
Confidence scoring, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
Pro API Example
GET /api/v2/pro/kevs/CVE-2023-27997
{
"cve_id": "CVE-2023-27997",
"title": "A heap-based buffer overflow vulnerability [CWE-122] in FortiOS version 7.2.4...",
"affected_vendor": "Fortinet",
"affected_product": "FortiOS-6K7K, FortiProxy, FortiOS",
"affected_versions": [
{ "vendor": "...", "product": "...", "status": "affected", "display_label": "..." }
],
"confidence": "Confirmed",
"cvss_score": 9.2,
"epss_score": null,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "...": "Pro API fields" },
"proof_of_concepts": [ "..." ],
"scanner_integrations": [ "..." ]
}