Cyber Resilience

CVE-2023-33302

Memory Safety in Fortinet Fortimail 5.4.0 – 5.4.12

Memory Safety
Published
31 March 2025
Modified
23 July 2025
Patch / advisory
View advisory
CVSS Score v3.1 4.7
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L
EPSS Score 0.0035 28th percentile
Risk Priority 37 floored blend · peak EPSS

Summary

CVE-2023-33302 is a medium-severity Classic Buffer Overflow (CWE-120) vulnerability in Fortinet Fortimail. Its CVSS base score is 4.7 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 28th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2023-33302 is a classic buffer overflow vulnerability (CWE-120) stemming from a buffer copy without checking the size of input. It affects the webmail and administrative interface in Fortinet FortiMail versions 6.4.0 through 6.4.4 and before 6.2.6, as well as the administrative interface in FortiNDR version 7.2.0 and before 7.1.0. The issue has a CVSS v3.1 base score of 4.7 (AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L), indicating medium severity.

An authenticated attacker with regular webmail access can exploit this vulnerability over the network with low complexity and no user interaction required. By sending specifically crafted HTTP requests, the attacker can trigger the buffer overflow, potentially leading to execution of unauthorized code or commands.

Fortinet's advisory FG-IR-21-023, available at https://fortiguard.fortinet.com/psirt/FG-IR-21-023, provides details on the vulnerability, including recommended patches and mitigation steps.

EU & UK References

Vulnerability Data

A buffer copy without checking size of input ('classic buffer overflow') in Fortinet FortiMail webmail and administrative interface version 6.4.0 through 6.4.4 and before 6.2.6 and FortiNDR administrative interface version 7.2.0 and before 7.1.0 allows an authenticated attacker with regular…

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webmail access to trigger a buffer overflow and to possibly execute unauthorized code or commands via specifically crafted HTTP requests.

CWE(s)
CWE-120

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-22627Same vendor: Fortinet
CVE-2025-46776Same vendor: Fortinet
CVE-2024-46663Same product: Fortinet Fortimail
CVE-2023-29177Same vendor: Fortinet
CVE-2025-32756Same product: Fortinet Fortimail
CVE-2023-36556Same product: Fortinet Fortimail
CVE-2023-48790Same product: Fortinet Fortindr
CVE-2026-25088Same product: Fortinet Fortindr
CVE-2025-53681Same product: Fortinet Fortimail
CVE-2025-54972Same product: Fortinet Fortimail

Affected Assets

fortinet
fortimail
5.4.0 — 5.4.12 · 6.0.0 — 6.0.11 · 6.2.0 — 6.2.7
fortinet
fortindr
1.1.0 — 7.2.1

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V5.2.1

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and analysis can find missing size checks before deployment.

SI-10 Information Input Validation good match

Input validation directly enforces size checks before buffer copies.

SA-8 Security and Privacy Engineering Principles partial match

Engineering principles require bounds checking and safe buffer handling in design.

SI-16 Memory Protection partial match

Memory protection limits the impact of an overflow once it occurs.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure development practices directly enforce bounds checking and input validation that prevent classic buffer overflows.

ID.RA-01 partial match
prevents

Vulnerability identification processes such as code review or scanning detect classic buffer overflows before exploitation.

PR.PS-02 partial match
prevents

Routine patching replaces vulnerable code containing unchecked buffer copies with corrected versions.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.28 Secure coding mostly match
prevents

Secure coding directly requires bounds-checked memory operations, addressing the root cause of CWE-120.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development and acceptance can detect buffer overflows through fuzzing and static analysis, though it does not prevent them at the source.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates processes that can include input validation and bounds checking to prevent buffer overflows.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify input-size validation and safe buffer handling to mitigate classic buffer overflows.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure system architecture and engineering principles promote defensive coding patterns that reduce the likelihood of unchecked buffer copies.

References