PatchTheCVECVE-2021-3378: FortiLogger 4.4.2.2 is affected by Arbitrary File Upload by sending a "Content-Type: image/png" header to Conf
CVE-2021-3378 is a critical-severity flaw (CVSS 9.8) affecting fortilogger. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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.
Why this priority
- Critical severity
- EPSS top 1%: very likely to be exploited
- Public exploit reference
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 9.8 (Critical) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 97.5% (top 1%) |
| CISA exploited list | No |
| Weakness | CWE-434 |
| Published | 2021-02-01 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Exact fixes by distribution
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
- GitHub PoC: erberkan/fortilogger_arbitrary_fileupload (23 stars)
- Exploit-DB: FortiLogger 4.4.2.2 - Unauthenticated Arbitrary File Upload (Metasploit)
- Metasploit: FortiLogger Arbitrary File Upload Exploit
- Nuclei scan template: FortiLogger 4.4.2.2 - Arbitrary File Upload
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2021-3378?
fortilogger: upgrade to 5.2.0. Exact commands for each OS are on this page.
Is CVE-2021-3378 being exploited?
CVE-2021-3378 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2021-3378 affect?
CVE-2021-3378 affects fortilogger. Severity is critical (CVSS 9.8). 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.
How urgent is CVE-2021-3378?
Priority 69/100. Critical severity; EPSS top 1%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action