CVE-2021-1429

SYSTEM code execution via insecure upgrade temporary file

Published May 6, 2021 · Updated Nov 8, 2024

Privilege escalation in Cisco Secure Client before 4.10.00093 allows local users to execute arbitrary code with SYSTEM privileges. During a Windows upgrade, the client creates a temporary executable with insecure permissions, allowing its contents to be overwritten before privileged execution. A valid Windows account and winning the timing window are required; successful exploitation grants SYSTEM-level code execution.

CVSS severity7.0
High
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Privilege escalation in Cisco Secure Client before 4.10.00093 allows local users to execute arbitrary code with SYSTEM privileges. During a Windows upgrade, the client creates a temporary executable with insecure permissions, allowing its contents to be overwritten before privileged execution. A valid Windows account and winning the timing window are required; successful exploitation grants SYSTEM-level code execution.

The record

CVE
CVE-2021-1429
Published
May 6, 2021
Updated
Nov 8, 2024
Vendor
ClamAV
Product
Cisco Secure Client
Classifications
CWE-378, CWE-427, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 6, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 8, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

ClamAV · Cisco Secure Clientversion=n/a

Published CVSS scores

7.2NIST National Vulnerability DatabaseAV:L/AC:L/Au:N/C:C/I:C/A:C
7.0Cisco Systems, Inc.CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8NIST National Vulnerability DatabaseCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-378Creation of Temporary File With Insecure Permissions
CWE-427Uncontrolled Search Path Element
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

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Your stack

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