CVE-2023-28804Network attack vector

Code execution via unsigned binary replacement

Published Oct 23, 2023 · Updated Oct 17, 2024

Improper signature verification in Zscaler Client Connector before 1.4.0.105 allows remote attackers to replace Linux binaries. The update path accepts replacement binaries without adequately verifying their cryptographic signatures, but Zscaler has not disclosed the responsible file or function. Network access without authentication or user interaction is sufficient, and a substituted binary executes with the connector's elevated privileges.

CVSS severity8.2
High
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper signature verification in Zscaler Client Connector before 1.4.0.105 allows remote attackers to replace Linux binaries. The update path accepts replacement binaries without adequately verifying their cryptographic signatures, but Zscaler has not disclosed the responsible file or function. Network access without authentication or user interaction is sufficient, and a substituted binary executes with the connector's elevated privileges.

The record

CVE
CVE-2023-28804
Published
Oct 23, 2023
Updated
Oct 17, 2024
Vendor
Zscaler
Product
Zscaler Client Connector
Classifications
CWE-347, CAPEC-549, T1553
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 23, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <1.4.0.105

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zscaler · Zscaler Client Connectorversion=0 <1.4.0.105

Published CVSS scores

8.2ZscalerCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature
CAPEC-549Local Execution of Code
T1553Subvert Trust Controls

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

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Your stack

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