VDB-394688 · CVE-2026-59565 · GCVE-0-2026-59565

Zscaler Client Connector prior 4.6.0.457/4.7.0.317/4.8.0.232/4.9.0.372 buffer overflow

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
8.7	$0-$5k	1.04+

Summaryinfo

A vulnerability classified as very critical was found in Zscaler Client Connector. This affects an unknown function. Such manipulation leads to buffer overflow. This vulnerability is listed as CVE-2026-59565. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as very critical, has been found in Zscaler Client Connector. Affected by this issue is an unknown function. The manipulation with an unknown input leads to a buffer overflow vulnerability. Using CWE to declare the problem leads to CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. Impacted is confidentiality, integrity, and availability. CVE summarizes:

A remotely exploitable buffer overflow bug can cause a local and kernel denial-of-service attack on affected versions of Zscaler Client Connector on Windows.

The advisory is shared for download at help.zscaler.com. This vulnerability is handled as CVE-2026-59565 since 07/06/2026. The exploitation is known to be easy. The attack may be launched remotely. Additional levels of successful authentication are necessary for exploitation. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 08/24/2026).

Upgrading to version 4.6.0.457, 4.7.0.317, 4.8.0.232 or 4.9.0.372 eliminates this vulnerability.

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Vendor

Zscaler

Name

Client Connector

CPE 2.3info

🔒

CPE 2.2info

🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.0
VulDB Meta Temp Score: 8.7

VulDB Base Score: 9.1
VulDB Temp Score: 8.7
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 8.8
CNA Vector (Zscaler): 🔒

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Client Connector 4.6.0.457/4.7.0.317/4.8.0.232/4.9.0.372

Timelineinfo

07/06/2026 CVE reserved
08/24/2026 +49 days Advisory disclosed
08/24/2026 +0 days VulDB entry created
08/24/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: help.zscaler.com
Status: Confirmed

CVE: CVE-2026-59565 (🔒)
GCVE (CVE): GCVE-0-2026-59565
GCVE (VulDB): GCVE-100-394688

Entryinfo

Created: 08/24/2026 16:17
Changes: 08/24/2026 16:17 (61)
Complete: 🔍
Cache ID: 216::103