CVE-2025-32756: Fortinet Multiple Products Stack-Based Buffer Overflow Vulnerability

What it is

A stack-based buffer overflow vulnerability [CWE-121] vulnerability in Fortinet FortiCamera 2.1.0 through 2.1.3, FortiCamera 2.0 all versions, FortiCamera 1.1 all versions, FortiMail 7.6.0 through 7.6.2, FortiMail 7.4.0 through 7.4.4, FortiMail 7.2.0 through 7.2.7, FortiMail 7.0.0 through 7.0.8, FortiNDR 7.6.0, FortiNDR 7.4.0 through 7.4.7, FortiNDR 7.2.0 through 7.2.4, FortiNDR 7.0.0 through 7.0.6, FortiRecorder 7.2.0 through 7.2.3, FortiRecorder 7.0.0 through 7.0.5, FortiRecorder 6.4.0 through 6.4.5, FortiVoice 7.2.0, FortiVoice 7.0.0 through 7.0.6, FortiVoice 6.4.0 through 6.4.10 allows a remote unauthenticated attacker to execute arbitrary code or commands via sending HTTP requests with specially crafted hash cookie.

Exploitation evidence

First exploit evidence seen: 2025-05-14 (earliest date across the sources below).

Exploited in the wild

• CISA KEV: listed since 2025-05-14. Source

Public exploit code

GitHub proof-of-concept repositories

5 public repositories from 5 accounts, first seen 2025-05-18. Most starred: kn0x0x/CVE-2025-32756-POC (191 stars), view repository.

Verify before running: public PoCs can be malicious. Read the code and only run it in an isolated lab. A PoC means exploit code is public, not that this CVE is exploited in the wild.

Sources: CISA KEV · nomi-sec/PoC-in-GitHub.

How to fix it

CISA required action

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. (source: CISA KEV)

Fixed versions

• fortinet fortimail: upgrade to 7.0.9 or later (affected from 7.0.0)
• fortinet fortimail: upgrade to 7.2.8 or later (affected from 7.2.0)
• fortinet fortimail: upgrade to 7.4.5 or later (affected from 7.4.0)
• fortinet fortimail: upgrade to 7.6.3 or later (affected from 7.6.0)
• fortinet fortindr: upgrade to 7.0.7 or later (affected from 7.0.0)
• fortinet fortindr: upgrade to 7.2.5 or later (affected from 7.2.0)
• fortinet fortindr: upgrade to 7.4.8 or later (affected from 7.4.0)
• fortinet fortirecorder: upgrade to 6.4.6 or later (affected from 6.4.0)
• fortinet fortirecorder: upgrade to 7.0.6 or later (affected from 7.0.0)
• fortinet fortirecorder: upgrade to 7.2.4 or later (affected from 7.2.0)
• fortinet fortivoice: upgrade to 6.4.11 or later (affected from 6.4.0)
• fortinet fortivoice: upgrade to 7.0.7 or later (affected from 7.0.0)

Derived from the NVD CPE configuration (versionEndExcluding / versionEndIncluding). Always confirm with the vendor advisory.

Vendor advisories and patches

• https://fortiguard.fortinet.com/psirt/FG-IR-25-254 (CISA KEV notes)

MITRE ATT&CK mitigations for this chain

• M1056 Pre-compromise (for T1608.001) : This technique cannot be easily mitigated with preventive controls since it is based on behaviors performed outside of the scope of enterprise defenses and controls.
• M1021 Restrict Web-Based Content (for T1133, T1059) : Restrict all traffic to and from public Tor nodes.
• M1030 Network Segmentation (for T1133, T1046) : Deny direct remote access to internal systems through the use of network proxies, gateways, and firewalls.
• M1042 Disable or Remove Feature or Program (for T1133, T1059, T1046) : Disable or block remotely available services that may be unnecessary.
• M1035 Limit Access to Resource Over Network (for T1133) : Limit access to remote services through centrally managed concentrators such as VPNs and other managed remote access systems.
• M1032 Multi-factor Authentication (for T1133) : Use strong two-factor or multi-factor authentication for remote service accounts to mitigate an adversary's ability to leverage stolen credentials, but be aware of [Multi-Factor Authentication Interception](https://attack.mitre.org/techniques/T1111) techniques for some two-factor authentication implementations.
• M1033 Limit Software Installation (for T1059) : Prevent user installation of unrequired command and scripting interpreters.
• M1045 Code Signing (for T1059) : Where possible, only permit execution of signed scripts.
• M1038 Execution Prevention (for T1059) : Use application control where appropriate. For example, PowerShell Constrained Language mode can be used to restrict access to sensitive or otherwise dangerous language elements such as those used to execute arbitrary Windows APIs or files (e.g., `Add-Type`).
• M1049 Antivirus/Antimalware (for T1059) : Anti-virus can be used to automatically quarantine suspicious files.

Detection Generic guidance

• Initial Access: Alert on unusual requests to the affected service (odd paths, oversized payloads, exploit strings) in WAF, reverse-proxy and application logs.
• Persistence: Look for new files in web roots, new scheduled tasks/services, and new accounts created after the exposure window.
• Execution: Watch for the service process spawning shells or script interpreters (cmd.exe, powershell, sh, bash, python) via EDR process-tree rules.
• Credential Access: Monitor for credential dumping, unusual LSASS access and sudden authentication from new sources.
• Discovery: Look for directory listing, file enumeration and reconnaissance commands from service accounts.
• Exfiltration: Watch for large or unusual outbound transfers from the affected host.

Response checklist Generic guidance

1. Inventory: find every instance of the affected product and version (include internet-facing and forgotten ones).
2. Patch or mitigate per the vendor advisory; if you cannot patch, remove internet exposure or apply the vendor workaround.
3. Assume compromise if the system was exposed before patching: hunt for the indicators in the advisory and review logs back to the disclosure date.
4. Rotate credentials and secrets stored on or used by the affected system if compromise cannot be ruled out.