CVE-2021-27964

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 47.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-03-05 · updated 2026-06-17
Weakness: CWE-434

Description

SonLogger before 6.4.1 is affected by Unauthenticated Arbitrary File Upload. An attacker can send a POST request to /Config/SaveUploadedHotspotLogoFile without any authentication or session header. There is no check for the file extension or content of the uploaded file.

Affected products

Sfcyazilim Sonlogger: before 6.4.1 — fixed in 6.4.1

How to fix

Upgrade to a fixed version: Sfcyazilim Sonlogger 6.4.1. Check the vendor advisory for mitigations.

References

http://packetstormsecurity.com/files/161793/SonLogger-4.2.3.3-Shell-Upload.html
https://github.com/erberkan/SonLogger-vulns
https://www.sonlogger.com/releasenotes
http://packetstormsecurity.com/files/161793/SonLogger-4.2.3.3-Shell-Upload.html
https://github.com/erberkan/SonLogger-vulns
https://www.sonlogger.com/releasenotes

Get alerted when CVE-2021-27964 or the next vulnerability affects your stack