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TI-2026-74600 Aliases CVE-2026-19377GHSA-v76q-8hm2-wrx6

Improper certificate validation in Cato Client tunnel handshake

Priority LOW 25CWE-295Published · Updated

Key facts

Attack vector
Adjacent network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
Spoofing
Confidentiality · integrity · availability
Low · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-295.

Summary

Cato Client for Windows, macOS, Linux, iOS and Android is affected before the fixed versions listed in the solution. The tunnel handshake does not properly validate certificates (CWE-295), so a man-in-the-middle attacker on an adjacent network can impersonate a Cato Point of Presence (PoP) server. The attacker can then intercept or modify tunnel traffic without privileges or user interaction.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00083 0th percentileScored 2026-11-07
Fix Fixed Cato Client for Windows (Cato Networks): 6.12.6Cato Client for macOS (Cato Networks): 6.1.1+3 more products

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Cato NetworksCato Client for Windowsbefore 6.12.66.12.6Patch availableCNA
Cato NetworksCato Client for macOSbefore 6.1.16.1.1Patch availableCNA
Cato NetworksCato Client for Linuxbefore 5.8.15.8.1Patch availableCNA
Cato NetworksCato Client for iOSbefore 5.95.9Patch availableCNA
Cato NetworksCato Client for Androidbefore 5.6.25.6.2Patch availableCNA
  • Cato Client for Windows VendorCato Networks Affected before 6.12.6 Fixed in 6.12.6 Patch available CNA
  • Cato Client for macOS VendorCato Networks Affected before 6.1.1 Fixed in 6.1.1 Patch available CNA
  • Cato Client for Linux VendorCato Networks Affected before 5.8.1 Fixed in 5.8.1 Patch available CNA
  • Cato Client for iOS VendorCato Networks Affected before 5.9 Fixed in 5.9 Patch available CNA
  • Cato Client for Android VendorCato Networks Affected before 5.6.2 Fixed in 5.6.2 Patch available CNA

Remediation

Upgrade Cato Client for Windows to 6.12.6, Cato Client for macOS to 6.1.1, Cato Client for Linux to 5.8.1, Cato Client for iOS to 5.9 and Cato Client for Android to 5.6.2.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

  • Fix · CNA Cato Client for Windows (Cato Networks) Fixed in 6.12.6
  • Fix · CNA Cato Client for macOS (Cato Networks) Fixed in 6.1.1
  • Fix · CNA Cato Client for Linux (Cato Networks) Fixed in 5.8.1
  • Fix · CNA Cato Client for iOS (Cato Networks) Fixed in 5.9
  • Fix · CNA Cato Client for Android (Cato Networks) Fixed in 5.6.2

Timeline

  1. 2026-10-15 Threatist record created from CVE-2026-19377
  2. 2026-10-16 Alias added: GHSA-v76q-8hm2-wrx6
  3. 2026-10-16 CISA SSVC decision points changed
  4. 2026-10-16 Priority changed: MEDIUM → LOW

References

Advisory 1

  • TI-2023-23578 An issue in CatoNetworks CatoClient before v.5.4.0 allows attackers to escalate… CVSS 3.1HIGH 8.1
  • TI-2024-06472 Improper input validation in Cato Networks SDP Client CVSS 3.1HIGH 8.8
  • TI-2025-12991 Cato's Socket WebUI is vulnerable to OS Command Injection CVSS 4.0HIGH 8.3
  • TI-2024-06474 Untrusted search path in Cato Networks SDP Client CVSS 3.1HIGH 8.8
  • TI-2024-06473 Incorrect default permissions in Cato Networks SDP Client CVSS 3.1HIGH 8.8
  • TI-2026-09234 Cato Networks SDP Client for Windows is vulnerable to Local Privilege Escalation CVSS 4.0HIGH 8.5
See all 12 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences