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Fencer Vulns
critical 9.8

CVE-2021-27964 in the critical feed json

SonLogger before 6.4.1 is affected by Unauthenticated Arbitrary File Upload.

published 2021-03-05 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-14682

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
47.5%
EPSS 47.5% chance of exploitation in 30 days, percentile 98%
public exploits
1
Exploit-DB, plus a Nuclei check

Summary

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.

Patch / fix

  • sfcyazilim sonlogger 6.4.1

Timeline

  1. Published
  2. First public exploit (EDB-49651)

Exploit prediction

47.52% chance of exploitation in the next 30 days, higher than 98% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • EDB-49651 SonLogger 4.2.3.3 - Unauthenticated Arbitrary File Upload (Metasploit) webapps, 2021-03-15
  • Nuclei template SonLogger - Arbitrary File Upload nuclei detection template
  • github.com https://github.com/erberkan/SonLogger-vulns referenced PoC, tagged "exploit" by a source, unverified
  • packetstormsecurity.com http://packetstormsecurity.com/files/161793/SonLogger-4.2.3.3-Shell-Upload.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness
  • CWE-434 Unrestricted Upload of File with Dangerous Type

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.