CVE-2021-26737
Privilege Escalation Using PID Reuse in ZCC macOS
The Zscaler Client Connector for macOS prior to 3.6 did not sufficiently validate RPC clients. A local adversary without sufficient privileges may be able to shutdown the Zscaler tunnel by exploiting a race condition.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Privilege Escalation Using PID Reuse in ZCC macOS
The Zscaler Client Connector for macOS prior to 3.6 did not sufficiently validate RPC clients. A local adversary without sufficient privileges may be able to shutdown the Zscaler tunnel by exploiting a race condition.
- Record
CVE-2021-26737- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-346
- Updated
- 2026-11-02
EUVDEUVD-2021-13524
The Zscaler Client Connector for macOS prior to 3.6 did not sufficiently validate RPC clients. A local adversary without sufficient privileges may be able to shutdown the Zscaler tunnel by exploiting a race condition.
- Record
EUVD-2021-13524- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-7x29-jh5v-6wwf
The Zscaler Client Connector for macOS prior to 3.6 did not sufficiently validate RPC clients. A...
The Zscaler Client Connector for macOS prior to 3.6 did not sufficiently validate RPC clients. A local adversary without sufficient privileges may be able to shutdown the Zscaler tunnel by exploiting a race condition.
- Record
GHSA-7x29-jh5v-6wwf- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-346
- Updated
- 2026-11-02
NVD
The Zscaler Client Connector for macOS prior to 3.6 did not sufficiently validate RPC clients. A local adversary without sufficient privileges may be able to shutdown the Zscaler tunnel by exploiting a race condition.
- Record
CVE-2021-26737- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - CVSS 3.1
- 4.7 Medium
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-346
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-26737 is a medium vulnerability (CVSS 5.5) in Zscaler Client Connector, published October 23, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.11%, the 1st percentile. No source names a fixed version.