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CVE-2023-27997

Exploitation: active CVSS 9.2 CRITICAL Ransomware: known use

CVSS base score: 9.2 (Critical) vendor CNA · v3.1

Score assigned by the vendor's own CVE Numbering Authority (CNA); CISA's Vulnrichment program adds a score only when the CNA omits one. Vulnrichment source record →

Fortinet FortiOS and FortiProxy SSL-VPN Heap-Based Buffer Overflow Vulnerability

Vendor: Fortinet   Product: FortiOS and FortiProxy SSL-VPN

Description

Fortinet FortiOS and FortiProxy SSL-VPN contain a heap-based buffer overflow vulnerability which can allow an unauthenticated, remote attacker to execute code or commands via specifically crafted requests.

Research & News Coverage

No mentions found in monitored research blogs or news feeds.

Referenced in Advisories

DateAdvisoryIssuer
2025-04-11 Fortinet Releases Advisory on New Post-Exploitation Technique for Known Vulnerabilities CISA
2025-02-13 ICSA-25-044-06: Siemens RUGGEDCOM APE1808 CISA
2025-01-28 A method to assess 'forgivable' vs 'unforgivable' vulnerabilities NCSC
2024-11-12 2023 Top Routinely Exploited Vulnerabilities CISA
2024-09-18 People's Republic of China-Linked Actors Compromise Routers and IoT Devices for Botnet Operations FBI
2024-08-29 #StopRansomware: RansomHub Ransomware CISA
2024-07-25 North Korea Cyber Group Conducts Global Espionage Campaign to Advance Regime’s Military and Nuclear Programs NSA
2024-07-25 North Korea Cyber Group Conducts Global Espionage Campaign to Advance Regime's Military and Nuclear Programs NSA

Lifecycle Timeline

Each milestone comes from a different source, so gaps between them are gaps in what those sources publish, not evidence that nothing happened. EPSS history for this CVE holds 226 points from 2023-06-17, tracked daily from 2026-09-09; earlier points are weekly, which dates a spike to within a week. Peak probability 92.4% on 2026-05-23.

Published Applicability

CVE List v5 (CNA container) 22 affected · 0 fixed · 0 not affected

Check whether a specific version is affected →

What each source publishes about which product versions carry this vulnerability, kept as written rather than merged. Absence here means no source has published applicability data, not that nothing is affected.

Detection & Exploitation

Scan
none published
Exploit / Pen Test
Host / SIEM

Coverage across public collections only: Nuclei and OpenVAS NVT (scan); Snort and Suricata ET Open (network); Sigma and YARA (host/SIEM); Metasploit, Exploit-DB, public GitHub repositories and NVD exploit references (exploit). Absence here means nothing public was found, not that detection is impossible.
GitHub PoC repositories are collected automatically by PoC-in-GitHub (CC0) and filtered to repositories that are still online, contain code, and are starred or at least two weeks old. They are still not vetted: some are fakes and some are malware. Treat them as evidence that code was published, not as code to run.
NVD exploit references are links NVD's analysts tag as exploits; they confirm an exploit was referenced but carry no date. This product uses data from the NVD but is not endorsed or certified by the NVD.
OpenVAS coverage derives from the Greenbone Community Feed, made available under the Open Database License (ODbL) v1.0; its individual Vulnerability Tests are licensed GNU GPL v2.

First seenToolEvidenceEarliest reference
2023-06-16 GitHub PoC Unvetted — public repository BishopFox/CVE-2023-27997-check +10 more

Metasploit is dated by the first commit of the module file, Exploit-DB by its publication date, and GitHub repositories by their creation date. GitHub PoC repositories are filtered (still online, contain code, starred or at least two weeks old) but not vetted: some are fakes and some are malware, so they show that code was published, not that it works or is safe to run. Evidence tiers are explained on the About page.

CISA Assessment (Vulnrichment / SSVC)

active
yes
total
—
9.2 CRITICAL
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
CWE-122 — Execute unauthorized code or commands
2024-10-23

Federal Remediation Window (BOD 26-04)

Yes — added 2023-06-13
yes
total control
If the asset isRemediate withinTable 1 row
Publicly exposed 3 days + forensic triage 1 of 16
Not publicly exposed 3 days + forensic triage 9 of 16

BOD 26-04 replaced the single KEV deadline of BOD 22-01 with four inputs: whether the asset is publicly exposed, KEV status, whether exploitation is automatable, and technical impact. Exposure belongs to each agency's asset, not to the CVE, so both outcomes are shown. Automatable and technical impact come from the CISA assessment above. Days are calendar days; for KEV entries the clock starts on the date it was added. Agencies make the final exposure call asset by asset, and may set shorter timelines.

D3FEND Countermeasures

Defensive techniques inferred by MITRE D3FEND from the underlying weakness (CWE-122) — general hardening and detection guidance for this weakness class, not a vendor patch for this specific CVE.

External References