Medium severity · published Oct 15, 2026
CVE-2026-19377
Improper certificate validation in Cato Client tunnel handshake
6.0
CVSS
0.1%
EPSS
No
On KEV
Description
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.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 0% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CC
Cato Client for Android · Cato Networks
before 5.6.2 · source: vendor
CC
Cato Client for Linux · Cato Networks
before 5.8.1 · source: vendor
CC
Cato Client for Windows · Cato Networks
before 6.12.6 · source: vendor
CC
Cato Client for iOS · Cato Networks
before 5.9 · source: vendor
CC
Cato Client for macOS · Cato Networks
before 6.1.1 · source: vendor