CVE-2025-54983VulnerabilityPublished 12 Nov 2025

CVE-2025-54983: Zscaler Client Connector · Missing Release of Resource after Effective Lifetime

Affects Zscaler Client ConnectorSource CVE Database V5

Not known to be exploited · CVSS 5.2 Medium.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

5.2Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Local
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Changed
Confidentiality: Low
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 12 Nov 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Zscaler Zscaler Client Connector	Affected =4.6 =4.7	Fixed in–

AI-suggested

1. Monitor Zscaler’s official channels for the release of patches addressing CVE-2025-54983 and apply updates to ZCC versions 4.6 and 4.7 promptly once available. 2. Until patches are deployed, implement strict endpoint security controls to limit local user privileges and prevent unauthorized access to affected systems. 3. Conduct network traffic analysis to identify anomalous patterns that may indicate bypass of forwarding controls, focusing on unexpected open ports or unusual routing behavior. 4. Employ host-based intrusion detection systems (HIDS) to monitor for suspicious activity related to the health check port or ZCC processes. 5. Review and tighten internal network segmentation to reduce the impact of potential lateral movement if forwarding controls are bypassed. 6. Educate IT and security teams about this specific vulnerability to enhance detection and response capabilities. 7. Consider temporary compensating controls such as firewall rules restricting local port usage or disabling non-essential diagnostic features if feasible. 8. Maintain comprehensive logging and audit trails for network traffic and endpoint activities to facilitate forensic investigations if exploitation is suspected.

Description

A health check port on Zscaler Client Connector on Windows, versions 4.6 < 4.6.0.216 and 4.7 < 4.7.0.47, which under specific circumstances was not released after use, allowed traffic to potentially bypass ZCC forwarding controls.

Impact

For European organizations, the impact of CVE-2025-54983 can be significant, particularly for those relying on Zscaler Client Connector to enforce network security policies and protect sensitive data. The ability to bypass forwarding controls may allow attackers or malicious insiders to exfiltrate data, access unauthorized network segments, or evade detection by security monitoring tools. This undermines confidentiality and integrity protections, potentially leading to data breaches or compliance violations under regulations such as GDPR. Critical sectors like finance, healthcare, and government, which often use Zscaler solutions for secure remote access and cloud security, are at heightened risk. The requirement for local privileges limits remote exploitation but does not eliminate risk, as insider threats or compromised endpoints could leverage this flaw. The lack of availability impact means service disruption is unlikely, but stealthy data leakage or policy circumvention could persist undetected. Overall, the vulnerability could weaken the security posture of European enterprises relying on Zscaler for network traffic control and monitoring.

CWE-772Missing Release of Resource after Effective Lifetime (opens in a new tab)
Base weaknessLikelihood of exploit: High
The product does not release a resource after its effective lifetime has ended, i.e., after the resource is no longer needed.
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Implementation
It is good practice to be responsible for freeing all resources you allocate and to be consistent with how and where you free resources in a function. If you allocate resources that you intend to free upon completion of the function, you must be sure to free the resources at all exit points for that function including…
Operation · Architecture and Design · Resource Limitation
Use resource-limiting settings provided by the operating system or environment. For example, when managing system resources in POSIX, setrlimit() can be used to set limits for certain types of resources, and getrlimit() can determine how many resources are available.
Attack patterns
HTTP DoS (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

help.zscaler.com/zscaler-client-connector/client-connector-app-release-summary-2025 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 19 Nov 2025, 05:47 UTC

WeaknessesCWE-772

Technical details

References

Community reviews

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