Improper certificate validation in Cato Client tunnel handshake

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

1. Oct 15, 2026 · NIST NVD

   Detected

   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.

2. Oct 15, 2026 · NIST NVD

   Updated

   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.

Affected

• vendor Cato Networks Cato Client for Androidversion unspecified
• vendor Cato Networks Cato Client for Linuxversion unspecified
• vendor Cato Networks Cato Client for Windowsversion unspecified
• vendor Cato Networks Cato Client for iOSversion unspecified
• vendor Cato Networks Cato Client for macOSversion unspecified

Sources

• CIRCL Vulnerability LookupVulnerability recordCVE-2026-19377

  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.

  vulnerability.circl.lu
• CVE.orgVulnerability recordCVE-2026-19377

  Official CVE identifier

  cve.org
• FIRST EPSSExploitation probabilityCVE-2026-19377

  30-day exploitation probability 0.1%

  first.org
• NIST NVDVulnerability recordCVE-2026-19377

  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.

  nvd.nist.gov

References

• Reference · knowledge.catonetworks.com