CVE-2021-27964

Name: CVE-2021-27964
Creator: NVD / NIST
Published: 2021-03-05T02:15:12.52+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 46.02%

Last modified Jun 17, 2026

CVE-2021-27964 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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. EPSS estimates a 46.02% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

46.02%

98.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-434

Affected Software

Vendor	Product	Versions
Sfcyazilim	Sonlogger	< 6.4.1

References

http://packetstormsecurity.com/files/161793/SonLogger-4.2.3.3-Shell-Upload.htmlExploit, Third Party Advisory, VDB Entry
https://github.com/erberkan/SonLogger-vulnsExploit, Third Party Advisory
https://www.sonlogger.com/releasenotesRelease Notes, Vendor Advisory
http://packetstormsecurity.com/files/161793/SonLogger-4.2.3.3-Shell-Upload.htmlExploit, Third Party Advisory, VDB Entry
https://github.com/erberkan/SonLogger-vulnsExploit, Third Party Advisory
https://www.sonlogger.com/releasenotesRelease Notes, Vendor Advisory

Timeline

Published: Mar 5, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-27964?

How severe is CVE-2021-27964?

CVE-2021-27964 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 46.02% probability of exploitation in the next 30 days.

How do I fix CVE-2021-27964?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-27964?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST