CVE-2021-34788

Root code execution via library verification race

Published Oct 6, 2021 · Updated Nov 7, 2024

Privilege escalation in Cisco Secure Client before 4.10.03104 allows local users to execute arbitrary code with root privileges. A race in shared-library signature verification lets crafted IPC messages alter which library the AnyConnect process loads after verification. A valid local account and an installed VPN Posture (HostScan) Module are required for root-level code execution.

CVSS severity7.0
High
EPSS probability0.18%
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 Cisco Secure Client before 4.10.03104 allows local users to execute arbitrary code with root privileges. A race in shared-library signature verification lets crafted IPC messages alter which library the AnyConnect process loads after verification. A valid local account and an installed VPN Posture (HostScan) Module are required for root-level code execution.

The record

CVE
CVE-2021-34788
Published
Oct 6, 2021
Updated
Nov 7, 2024
Vendor
ClamAV
Product
Cisco Secure Client
Classifications
CWE-367, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 6, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 7, 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=n/a

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

ClamAV · Cisco Secure Clientversion=n/a

Published CVSS scores

7.0CiscoCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
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