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Improper Certificate ValidationWeakness · CWE-295

CVE-2025-0309

MEDIUM · 6.0 CVSS v4.0 Published 2025-08-14
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
62/100
Remediation priority · Elevated
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
An insufficient validation on the server connection endpoint in Netskope Client allows local users to elevate privileges on the system. The insufficient validation allows Netskope Client to connect to any other server with Public Signed CA TLS certificates and send specially crafted responses to elevate privileges.

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

Netskope Client contains insufficient validation on its server connection endpoint, allowing the client to connect to arbitrary servers possessing valid Public Signed CA TLS certificates. Attackers on the same network or with control over DNS can redirect the client to a malicious server that sends specially crafted responses enabling local privilege escalation.

MitigationApply vendor patch when available; in the interim, restrict local user access to the Netskope Client process and monitor for unusual network connections from the client.

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

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
Physical
Complexity
Low
Privileges
Low
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:P/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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. Identify Netskope Client installation
    Check for Netskope Client process or service running on the system. On Windows, look in Program Files or Program Files (x86) for Netskope. On macOS, check /Applications for Netskope Client. On Linux, check /opt or /usr/local for netskope directories.
    Affected if Netskope Client is found running or installed on the system
  2. Determine installed Netskope Client version
    Locate the Netskope Client executable or version file. On Windows, right-click the executable and view Properties > Details, or check the Windows Registry under HKLM\SOFTWARE\Netskope or HKLM\SOFTWARE\WOW6432Node\Netskope for a Version value. On macOS, right-click the app and select Get Info. On Linux, run 'netskope_client --version' or check version files in the installation directory.
    Affected if The installed version is lower than the patched version released by Netskope for this CVE
  3. Inspect server endpoint configuration
    Examine the Netskope Client configuration files or registry keys for the configured server URL. On Windows, check the ClientID or ServerURL registry values under HKLM\SOFTWARE\Netskope or HKCU\Software\Netskope. Look for entries that specify the Netskope server the client should connect to.
    Affected if The client configuration allows connection to arbitrary servers or contains an unexpected/unknown server URL
  4. Monitor for unusual network connections
    Use network monitoring tools (netstat, Wireshark, Process Monitor) to observe which remote servers the Netskope Client process attempts to connect to. Verify that connections only go to legitimate Netskope infrastructure domains.
    Affected if The client connects to servers other than official Netskope servers or displays DNS resolution anomalies for netskope domains
  5. Verify endpoint validation behavior
    If possible, attempt to observe or log the TLS certificate validation behavior. Check if the client accepts certificates from arbitrary CAs or only validates against a specific Netskope certificate chain.
    Affected if The client accepts TLS connections from any server with a valid CA-signed certificate without strict endpoint validation

The environment is affected if Netskope Client is installed and version information confirms the vulnerability exists, particularly if the client accepts connections to arbitrary TLS servers or connects to unexpected endpoints.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor patch when available; in the interim, restrict local user access to the Netskope Client process and monitor for unusual network connections from the client.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA3.0 h
24.0 hours of engineering $4,200
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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-2025-0309 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
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