MEDIUM
CVE-2021-36809
NVD-CWE-noinfoPublished: March 8, 2022· Updated: Jun 17, 2026
6.0
CVSS v3.1
Official Description
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.
Technical Analysis
CVE-2021-36809 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires high privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
A successful exploit results in full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 6.0.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorLocal
Attack ComplexityLow
Privileges Req.High
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H
Affected Vendors & Products
sophos1 product(s)
ssl vpn client
Source: NVD CPE · 1 total CPE entries
Exploit & PoC Resources
NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
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GitHub PoC Search
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Rapid7 / Metasploit
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PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
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Official Patches & Advisories
All References (2)
Quick Facts
CVE IDCVE-2021-36809
CVSS Score6.0 / 10
SeverityMEDIUM
WeaknessNVD-CWE-noinfo
CISA KEVNo
Affected1 vendor(s)
PublishedMar 8, 2022
Related CVEs (NVD-CWE-noinfo)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-36809 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.