Cyber Resilience

CVE-2021-3378

Fortilogger ≤ 5.2.0

Public PoCHigh EPSS
Published
01 February 2021
Modified
21 November 2024
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.98 99.9th percentile
Risk Priority 97 floored blend · peak EPSS

Summary

CVE-2021-3378 is a critical-severity Unrestricted Upload of File with Dangerous Type (CWE-434) vulnerability in Fortilogger Fortilogger. Its CVSS base score is 9.8 (Critical).

Operationally, ranked in the top 0.1% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

FortiLogger 4.4.2.2 is affected by Arbitrary File Upload by sending a "Content-Type: image/png" header to Config/SaveUploadedHotspotLogoFile and then visiting Assets/temp/hotspot/img/logohotspot.asp.

CWE(s)

Related Threats

Likely ATT&CK TechniquesAI

Techniques this vulnerability likely enables, inferred from its description, weakness type, and attributed-actor tradecraft. Confidence is per-technique.

T1105 Ingress Tool Transfer Command And Controlconfidence: HIGH
Arbitrary file upload allows an attacker to transfer a malicious file to the target system.
T1505.003 Web Shell Persistenceconfidence: HIGH
Uploaded file placed in web-accessible directory can be executed as a web shell.
T1190 Exploit Public-Facing Application Initial Accessconfidence: HIGH
Vulnerability in a public-facing application enables initial remote compromise.
inferred from description + CWE · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2020-37009Shared CWE-434
CVE-2023-50922Shared CWE-434
CVE-2024-52769Shared CWE-434
CVE-2023-1797Shared CWE-434
CVE-2023-6102Shared CWE-434
CVE-2024-3521Shared CWE-434
CVE-2024-58281Shared CWE-434
CVE-2026-44088Shared CWE-434
CVE-2024-2381Shared CWE-434
CVE-2023-6090Shared CWE-434

Affected Assets

fortilogger
fortilogger
≤ 5.2.0

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)
  • V5.1.1

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-434

Requiring identifiable owners for portable devices reduces the attack surface for unrestricted uploads of dangerous file types via anonymous media.

addresses: CWE-434

Dangerous file uploads can be detonated in the chamber to determine malice before any production write or execution occurs.

addresses: CWE-434

Prevents unrestricted writing of arbitrary or malicious firmware by keeping hardware write-protect enabled except under tightly controlled manual procedures.

addresses: CWE-434

Scans files from external sources on download/open/execute, blocking unrestricted uploads of dangerous file types.

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-05 mostly match
prevents

Restricting execution of unauthorized software directly blocks dangerous uploaded files from running.

PR.PS-01 partial match
prevents

Hardened configuration baselines can enforce allowed file types and processing rules.

PR.PS-06 partial match
prevents

Secure development practices include input validation and file-type restrictions that prevent this weakness.

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.

detects

Configuration and acceptance testing verify that file-upload handling enforces allowed types and does not permit dangerous content to be stored or executed.

prevents

Secure-coding guidelines and security testing explicitly address restrictions on allowed file types and upload handling, reducing the risk that dangerous file uploads are accepted without validation.

prevents

Mandated testing for malicious content and known vulnerabilities reduces the likelihood that an outsourced component will contain or accept dangerous file types that could later be uploaded or executed.

mitigates

Application allow-listing and pre-use scanning of received files directly blocks the introduction of executable content that has not been vetted, eliminating the primary vector for unrestricted dangerous file uploads.

References