Cato Client for Windows Tunnel Handshake certificate validation

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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3.7$0-$5k3.05-

Summaryinfo

A vulnerability, which was classified as problematic, was found in Cato Client for Windows, Client for macOS, Client for Linux, Client for iOS and Client for Android. Affected by this issue is some unknown functionality of the component Tunnel Handshake. Executing a manipulation can lead to certificate validation. This vulnerability is registered as CVE-2026-19377. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability has been found in Cato Client for Windows, Client for macOS, Client for Linux, Client for iOS and Client for Android and classified as problematic. This vulnerability affects some unknown functionality of the component Tunnel Handshake. The manipulation with an unknown input leads to a certificate validation vulnerability. The CWE definition for the vulnerability is CWE-295. The product does not validate, or incorrectly validates, a certificate. As an impact it is known to affect integrity. CVE summarizes:

Improper certificate validation in the tunnel handshake in Cato Client allows a man-in-the-middle attacker to impersonate a Cato Point of Presence (PoP) server and intercept or modify tunnel traffic.

The advisory is shared for download at knowledge.catonetworks.com. This vulnerability was named CVE-2026-19377 since 08/09/2026. The exploitation appears to be difficult. The attack can be initiated remotely. No form of authentication is required for a successful 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 10/15/2026). The MITRE ATT&CK project declares the attack technique as T1587.003.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-101881). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

Vendor

Name

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 3.7
VulDB Meta Temp Score: 3.7

VulDB Base Score: 3.7
VulDB Temp Score: 3.7
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Certificate validation
CWE: CWE-295 / CWE-287
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

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

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

08/09/2026 CVE reserved
10/15/2026 +67 days Advisory disclosed
10/15/2026 +0 days VulDB entry created
10/15/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: knowledge.catonetworks.com
Status: Confirmed

CVE: CVE-2026-19377 (🔒)
GCVE (CVE): GCVE-0-2026-19377
GCVE (VulDB): GCVE-100-420520
EUVD: 🔒
scip Labs: https://www.scip.ch/en/?labs.20180712

Entryinfo

Created: 10/15/2026 09:36
Updated: 10/15/2026 10:13
Changes: 10/15/2026 09:36 (64), 10/15/2026 10:13 (1)
Complete: 🔍
Cache ID: 216::103

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

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