Time-of-check time-of-use race condition in Cisco AnyConnect Secure Mobility Client
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- High
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
A vulnerability in the shared library loading mechanism of Cisco AnyConnect Secure Mobility Client for Linux and Mac OS could allow an authenticated, local attacker to perform a shared library hijacking attack on an affected device if the VPN Posture (HostScan) Module is installed on the AnyConnect client. This vulnerability is due to a race condition in the signature verification process for shared library files that are loaded on an affected device. An attacker could exploit this vulnerability by sending a series of crafted interprocess communication (IPC) messages to the AnyConnect process. A successful exploit could allow the attacker to execute arbitrary code on the affected device with root privileges. To exploit this vulnerability, the attacker must have a valid account on the system.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Cisco | Cisco AnyConnect Secure Mobility Client | all versions | — | No fix listed | CNA |
- Cisco AnyConnect Secure Mobility Client VendorCisco Affected all versions Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2021-34788
- 2026-10-03 Alias added: GHSA-mh72-74m7-v766
References
More Cisco Anyconnect Secure Mobility Client vulnerabilities
- TI-2020-02982 Cisco AnyConnect Secure Mobility Client for Windows DLL Hijacking Vulnerability KEVCVSS 3.1HIGH 7.8
- TI-2020-02715 Cisco AnyConnect Secure Mobility Client for Windows Uncontrolled Search Path Vulnerability KEVCVSS 3.1MEDIUM 6.5
- TI-2011-01789 The helper application in Cisco AnyConnect Secure Mobility Client (formerly AnyConnect… CVSS 2.0HIGH 7.6
- TI-2011-01790 The helper application in Cisco AnyConnect Secure Mobility Client (formerly AnyConnect… CVSS 2.0HIGH 9.3
- TI-2012-02179 The VPN downloader implementation in the WebLaunch feature in Cisco AnyConnect Secure… CVSS 2.0HIGH 9.3
- TI-2023-06884 Incorrect default permissions in Cisco Secure Client CVSS 3.1HIGH 7.8
Sources
- CVE-2021-34788 · CVE Program
- CVE-2021-34788 · NVD
- FIRST EPSS
- GHSA-mh72-74m7-v766 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences