CVE-2023-42784
Fortinet Fortiweb 7.0.0 – 7.4.7
Raw vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:LCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2023-42784 is a medium-severity Improper Handling of Syntactically Invalid Structure (CWE-228) vulnerability in Fortinet Fortiweb. Its CVSS base score is 5.6 (Medium).
Operationally, ranked at the 31th 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 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-2023-42784 is an improper handling of syntactically invalid structures (CWE-228) vulnerability affecting Fortinet FortiWeb in versions 7.4.0 through 7.4.6, 7.2.0 through 7.2.10, and 7.0.0 through 7.0.10. The issue stems from inadequate validation of crafted HTTP/S requests, enabling attackers to execute unauthorized code or commands.
Remote attackers require no privileges or user interaction to exploit this over the network (AV:N/PR:N/UI:N), but it demands high attack complexity (AC:H) with unchanged scope (S:U). Successful exploitation yields low impacts across confidentiality, integrity, and availability (C:L/I:L/A:L), for an overall CVSS v3.1 score of 5.6.
Mitigation details, including patches, are outlined in the Fortinet PSIRT advisory FG-IR-23-115 at https://fortiguard.fortinet.com/psirt/FG-IR-23-115.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-47214
Vulnerability Data
An improper handling of syntactically invalid structure in Fortinet FortiWeb at least verions 7.4.0 through 7.4.6 and 7.2.0 through 7.2.10 and 7.0.0 through 7.0.10 allows attacker to execute unauthorized code or commands via HTTP/S crafted requests.
- CWE(s)
Related Threats
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
SI-10 requires validity checks on information inputs, directly stopping syntactically malformed data from being processed without proper handling.
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.8.25 mandates secure SDLC practices (secure coding guidelines, security requirements, checkpoints, testing including code scans) that reach improper syntactic handling during development; this prevents exploitation for many cases but leaves a bounded remainder (e.g. non-code-structure inputs, runtime parsers, or incomplete guideline application)
Application security requirements include explicit rules for input validation and malformed-data handling.
A.8.27 mandates security-by-design principles including data validation/sanitization, distrust-external-input, secure architecture reviews against attack patterns, and zero-trust verification; this reaches a minority slice of CWE-228 (invalid structure in external inputs) but leaves most instances (e.g. internal malformed data, non-input structures, parser differentials) unaddressed as the clause sets process rather than mandating complete syntactic enforcement everywhere.
Secure coding explicitly requires validation of all input syntax and structure, directly eliminating CWE-228.
Security testing can detect malformed-input issues but does not itself implement the handling logic.
Hardening callouts derived
DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.
- No fine-grained STIG row for CWE-228, a class-level weakness, and none of its children carries one either.