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Fencer Vulns
medium 6.1

CVE-2021-36809 json

A local attacker can overwrite arbitrary files on the system with VPN client logs using administrator privileges, potentially resulting in…

published 2022-03-07 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-23385

cvss
6.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 13%
public exploits
0
none known

Summary

A local attacker can overwrite arbitrary files on the system with VPN client logs using administrator privileges, potentially resulting in a denial of service and data loss, in all versions of Sophos SSL VPN client.

Exploit prediction

0.23% chance of exploitation in the next 30 days, higher than 13% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.1 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H
NVD 3.1 6.0 CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H
NVD 2.0 3.6 AV:L/AC:L/Au:N/C:N/I:P/A:P

Affected products

  • Sophos SSL VPN client

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.