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Client ConnectorApplication · Zscaler

CVE-2023-28793

HIGH · 7.8 CVSS v3.1 Published 2023-10-23
Fix available
A fix is available. Upgrade to 1.3.1.6 or later.
See remediation →
80/100
Remediation priority · High
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Buffer overflow vulnerability in the signelf library used by Zscaler Client Connector on Linux allows Code Injection. This issue affects Zscaler Client Connector for Linux: before 1.3.1.6.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

Buffer overflow vulnerability in the signelf library (used for ELF binary signing) in Zscaler Client Connector for Linux allows arbitrary code injection. This is a code execution vulnerability that could allow an attacker to execute malicious code on affected Linux systems.

MitigationUpdate Zscaler Client Connector for Linux to version 1.3.1.6 or later to remediate the buffer overflow in the signelf library.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Client ConnectorApplication
Affected:< 1.3.1.6

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify Zscaler Client Connector is installed
    Use your system's package manager to list installed packages, or search for Zscaler-related processes or services running on the system
    Affected if Zscaler Client Connector is present on the system
  2. Determine the installed version
    Run the appropriate command to query the Zscaler Client Connector version (for example, using the package manager or running 'zscaler --version' if available)
    Affected if The returned version is lower than 1.3.1.6
  3. Locate the signelf library
    Search for the signelf library file on the system if present - this is the library containing the vulnerable code
    Affected if The signelf library exists and its version cannot be determined or matches the vulnerable client version
  4. Check for ELF binary signing activity
    Review any logs or configurations indicating use of the signelf library for ELF binary signing operations
    Affected if The signelf functionality is actively being used on the system
  5. Verify the service is running
    Check if the Zscaler Client Connector service or daemon is currently running on the Linux system
    Affected if The Zscaler Client Connector service is active and the installed version is below 1.3.1.6

The system is affected if Zscaler Client Connector for Linux is installed with a version lower than 1.3.1.6 and the signelf library is present or in use.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 1.3.1.6 or later
Fixed in 1.3.1.6
Interim mitigation

Update Zscaler Client Connector for Linux to version 1.3.1.6 or later to remediate the buffer overflow in the signelf library.

Recommended fix High confidence

Zscaler Client Connector for Linux version 1.3.1.6 or later

  1. 1. Identify the current installed version of Zscaler Client Connector on the Linux system using package manager (e.g., dpkg -i, rpm -qi, or apt list --installed)
  2. 2. Download the latest Zscaler Client Connector for Linux version 1.3.1.6 or later from the official Zscaler download portal or refer to help.zscaler.com for the correct package
  3. 3. Stop the Zscaler Client Connector service before upgrading (e.g., systemctl stop zscaler or similar command based on init system)
  4. 4. Upgrade the package using the appropriate package manager for your Linux distribution (e.g., dpkg -i for Debian/Ubuntu, rpm -U for RHEL/CentOS)
  5. 5. Verify the new version is installed correctly
  6. 6. Start the Zscaler Client Connector service (e.g., systemctl start zscaler)
  7. 7. Confirm the service is running and the version is 1.3.1.6 or later
Caveat Review Zscaler release notes for any configuration or dependency changes between your current version and 1.3.1.6

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Client Connector Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-28793 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data