Security readout for executives and security teams
Plain-English summary
On affected Macs, Zscaler Client Connector before version 3.7 could let a local user run code as root through unsafe PATH handling. This is a high-impact endpoint privilege escalation, but it requires local access and the provided sources do not show active exploitation.
Executive priority
Treat this as a high-priority endpoint patching item for Mac fleets using Zscaler Client Connector. It is not internet-exposed, but successful abuse could give an insider or already-present attacker root control on a device.
Technical view
CVE-2021-26738 is a CWE-426 untrusted search path issue in Zscaler Client Connector for macOS prior to 3.7. A low-privileged local adversary may influence PATH resolution and achieve root code execution. CVSS 3.1 is 7.8, with high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is likely limited to macOS endpoints running Zscaler Client Connector versions earlier than 3.7. Organizations without ZCC on macOS, or already on 3.7 or later, are not indicated as exposed by the supplied sources.
Exploitation context
The vulnerability is local, low-complexity, and requires low privileges but no user interaction. The source bundle marks CISA KEV as false, and no cited source states active exploitation or public weaponization.
Researcher notes
The public details are sparse. The CVE identifies PATH-based untrusted search path behavior and root escalation potential, but the bundle does not include exploit mechanics, affected build ranges beyond prior to 3.7, or detailed vendor remediation notes.
Mitigation direction
- Upgrade Zscaler Client Connector for macOS to version 3.7 or later.
- Check Zscaler release guidance before deployment.
- Prioritize managed Mac fleets where local users can execute software.
- Restrict unnecessary local privileges on affected macOS endpoints.
- Monitor vendor advisories for any updated remediation guidance.
Validation and detection
- Inventory macOS endpoints with Zscaler Client Connector installed.
- Verify each installed ZCC version is 3.7 or later.
- Confirm endpoint management deployed the approved ZCC package.
- Review endpoint telemetry for unexpected privileged process activity near ZCC.
- Document any exceptions with compensating controls and upgrade dates.
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-426: 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 lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-26738 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
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/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:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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.
Untrusted Search Path
Untrusted Search Path represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.