CVE-2021-1237
highpriority · track · 31EPSS 0.004 · 35 %ileEURUUSEPSS · scored 2026-10-27
A vulnerability in the Network Access Manager and Web Security Agent components of Cisco AnyConnect Secure Mobility Client for Windows could allow an authenticated, local attacker to perform a DLL injection attack. To exploit this vulnerability, the attacker would need to have valid credentials on the Windows system. The vulnerability is due to insufficient validation of resources that are loaded by the application at run time. An attacker could exploit this vulnerability by inserting a configuration file in a specific path in the system which, in turn, causes a malicious DLL file to be loaded when the application starts. A successful exploit could allow the attacker to execute arbitrary code on the affected machine with SYSTEM privileges.
remediations
Vendor fix, mitigation, or workaround guidance, as published by each source.
A vendor fix is available.
- FixedCisco Secure Clientcisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (4)
Products and version ranges known to be affected.
- cisco anyconnect secure mobility client< 4.9.04043nvdUScpe:2.3:a:cisco:anyconnect_secure_mobility_client:*:*:*:*:*:*:*:*
advisories (1)
Vendor and ecosystem advisories describing this.
- cisco-sa-anyconnect-dll-injec-pQnryXLfCisco AnyConnect Secure Mobility Client for Windows DLL Injection Vulnerability2021-01-13csaf · cisco_csafUS
A vulnerability in the Network Access Manager and Web Security Agent components of Cisco AnyConnect Secure Mobility Client for Windows could allow an authenticated, local attacker to perform a DLL injection attack. To exploit this vulnerability, the attacker would need to have valid credentials on the Windows system. The vulnerability is due to insufficient validation of resources that are loaded by the application at run time. An attacker could exploit this vulnerability by inserting a configuration file in a specific path in the system which, in turn, causes a malicious DLL file to be loaded when the application starts. A successful exploit could allow the attacker to execute arbitrary code on the affected machine with SYSTEM privileges. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-anyconnect-dll-injec-pQnryXLf ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-anyconnect-dll-injec-pQnryXLf"]
also known as (4)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (6)
External citations — patches, advisories, analysis.
- https://nvd.nist.gov/vuln/detail/CVE-2021-1237cnnvd
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-anyconnect-dll-injec-pQnryXLfcnnvd
- https://vigilance.fr/vulnerability/Cisco-AnyConnect-Secure-Mobility-Client-executing-DLL-code-via-Network-Access-Manager-and-Web-Security-Agent-34311cnnvd
- https://www.auscert.org.au/bulletins/ESB-2021.0133/cnnvd
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-anyconnect-dll-injec-pQnryXLfenisa_euvd
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-anyconnect-dll-injec-pQnryXLfVendor Advisorynvd
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