CVE-2021-20106

Host privilege escalation via crafted file upload

Published Jul 21, 2021 · Updated Aug 3, 2024

Privilege escalation in Tenable Nessus Agent 8.2.5 and earlier allows local users with Nessus administrator access to gain host administrator privileges. Tenable identifies a specially crafted file upload as the trigger but has not disclosed the responsible component or unsafe file operation. Exploitation requires Nessus administrator access and user interaction; success grants administrator control of the host.

CVSS severity7.7
High
EPSS probability1.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Privilege escalation in Tenable Nessus Agent 8.2.5 and earlier allows local users with Nessus administrator access to gain host administrator privileges. Tenable identifies a specially crafted file upload as the trigger but has not disclosed the responsible component or unsafe file operation. Exploitation requires Nessus administrator access and user interaction; success grants administrator control of the host.

The record

CVE
CVE-2021-20106
Published
Jul 21, 2021
Updated
Aug 3, 2024
Vendor
Tenable
Product
Nessus Agent
Classifications
T1068
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Jul 21, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Nessus Agent 8.2.5 and earlier

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Tenable · Nessus Agentversion=Nessus Agent 8.2.5 and earlier

Published CVSS scores

7.7TenableCVSS:3.0/AV:L/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:H
6.5NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H
8.5NVDAV:N/AC:M/Au:S/C:C/I:C/A:C
6.9TenableCVSS:3.0/AV:L/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C
5.3TenableAV:L/AC:L/Au:S/C:C/I:C/A:C/E:POC/RL:OF/RC:C
6.8TenableAV:L/AC:L/Au:S/C:C/I:C/A:C

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo