Security readout for executives and security teams
Plain-English summary
CVE-2021-1496 is a local privilege escalation issue in Cisco AnyConnect Secure Mobility Client for Windows. A logged-in attacker could abuse install, uninstall, or upgrade handling to run code as SYSTEM. This matters most on shared workstations, VPN user endpoints, and systems where low-privilege local access is realistic.
Executive priority
Treat as a high-priority endpoint hardening and patch-management item, not an internet-exposed emergency. The business risk is privilege escalation on VPN client machines after local compromise or misuse of valid credentials.
Technical view
The vulnerability involves DLL or executable hijacking during AnyConnect for Windows install, uninstall, and upgrade processes. Cisco rates it CVSS 7.0 high: local attack vector, high complexity, low privileges required, no user interaction, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is limited to Windows systems running Cisco AnyConnect Secure Mobility Client. The supplied sources do not list exact affected or fixed versions, so teams need product inventory and Cisco advisory review.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation. Exploitation requires valid Windows credentials and local access, but success could produce SYSTEM-level code execution on the affected endpoint.
Researcher notes
Evidence supports local authenticated privilege escalation through hijacking of DLL or executable use in maintenance flows. The bundle lacks affected version detail, fixed release detail, exploit indicators, and proof of active exploitation.
Mitigation direction
- Review Cisco advisory for affected and fixed AnyConnect versions.
- Upgrade affected Windows AnyConnect clients using vendor guidance.
- Prioritize shared endpoints and systems with many local users.
- Limit unnecessary local logon access on VPN client systems.
- Monitor install, uninstall, and upgrade activity for anomalies.
Validation and detection
- Inventory Windows hosts running Cisco AnyConnect Secure Mobility Client.
- Compare installed versions against Cisco advisory guidance.
- Confirm whether install, uninstall, or upgrade workflows occur on endpoints.
- Check endpoint controls for suspicious privileged process creation.
- Document systems where valid local user access is broadly available.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-378: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-1496 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H15.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7HighVector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20210505 Cisco AnyConnect Secure Mobility Client for Windows DLL and Executable Hijacking VulnerabilitiesCVE reference · vendor-advisory, x_refsource_CISCO
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Creation of Temporary File With Insecure Permissions
Creation of Temporary File With Insecure Permissions represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.