CVE-2023-27997
CriticalExploitedPublic exploitA 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…
Published Jul 11, 2023 · Updated Jul 31, 2026 · Also known as TR-23-0339
Key Facts
Patch immediately- CVE-2023-27997 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting FortiProxy (Fortinet), FortiOS (Fortinet), FortiOS-6K7K.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jun 12, 2023 and is known to be used in ransomware campaigns. Public exploit code is available.
- EPSS estimates a 86% probability of exploitation in the next 30 days.
- Fixed versions are available, including FortiOS <=6.0.16, FortiProxy <=1.1.6, FortiProxy 1.1.6.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
86%
Higher than 99.7% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings, used by ransomware
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2023-27997 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
Description
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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Jun 13, 2023 | Jul 4, 2023 | Known |
| Industry KEV feed | Jun 12, 2023 | Jul 4, 2023 | Known |
| CIRCL KEV | Jun 13, 2023 | Jul 4, 2023 | Known |
| ENISA EUVD | Jun 13, 2023 | n/a | Not reported |
Required action: Apply updates per vendor instructions.
Affected Products
16 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| FortiProxyFortinet | >= 7.2.0 | 1.1.6 |
| FortiOSFortinet | 6.0.10, 6.2.4, 6.2.6, 6.2.7, 6.4.10, 6.4.12, 6.4.2, 6.4.6 | 6.0.16 |
| FortiOS-6K7K | >= 7.0.10 | n/a |
Patched Releases
FortiOS
<=6.0.16
FortiProxy
<=1.1.6
Timeline
Added to Industry KEV feed
Jun 12, 2023
Added to CISA KEV
Jun 13, 2023
Added to CIRCL KEV
Jun 13, 2023
Added to ENISA EUVD
Jun 13, 2023
Publicly disclosed
Jul 11, 2023
Last updated
Jul 31, 2026
Weakness Type
- CWE-122 Heap-based Buffer Overflow
- CWE-787 Out-of-bounds Write
References
- advisoryhttp://olympecyberdefense.fr/1193-2/
- advisoryhttps://fortiguard.com/psirt/FG-IR-20-014
- advisoryhttps://fortiguard.com/psirt/FG-IR-22-229
- advisoryhttps://fortiguard.com/psirt/FG-IR-22-332
- advisoryhttps://fortiguard.com/psirt/FG-IR-22-393
FAQ
Common Questions.
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…
Affected: FortiProxy (Fortinet) versions >= 7.2.0; FortiOS (Fortinet) versions 6.0.10, 6.2.4, 6.2.6, 6.2.7, 6.4.10, 6.4.12, 6.4.2, 6.4.6; FortiOS-6K7K versions >= 7.0.10. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jun 12, 2023 and is known to be used in ransomware campaigns.
Yes. It was added on Jun 13, 2023 with a federal remediation due date of Jul 4, 2023.
Public exploit code is available.
Fixed versions are available, including FortiOS <=6.0.16, FortiProxy <=1.1.6, FortiProxy 1.1.6.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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