Xcitium Client Security (XCS) before 13.8.2.10019 and Comodo Internet Security (CIS) through 12.3.4.8162 (fix expected by 2026 Q3) contain an integer underflow vulnerability in the firewall driver Inspect.sys that allows remote unauthenticated attackers to crash the system by sending a crafted IPv6 packet with a declared payload length smaller than the sum of its extension-header lengths. The unsigned 64-bit payload-length value underflows to a near-maximal integer, triggering an out-of-bounds read and oversized memcpy in the Windows kernel at DISPATCHLEVEL, resulting in a blue screen of death even on hosts with all ports blocked.

The Antivirus component in Comodo Internet Security before 5.3.174622.1216 does not check whether X.509 certificates in signed executable files have been revoked, which has unknown impact and remote attack vectors.

The Antivirus component in Comodo Internet Security before 4.1.150349.920 allows remote attackers to cause a denial of service (application crash) via a crafted file.

The Antivirus component in Comodo Internet Security before 5.3.175888.1227 does not check whether X.509 certificates in signed executable files have been revoked, which has unknown impact and remote attack vectors.

The Antivirus component in Comodo Internet Security before 3.11.108364.552 allows remote attackers to cause a denial of service (memory consumption) via a crafted compressed file.

Comodo Internet Security before 3.9.95478.509 allows remote attackers to bypass malware detection in an RAR archive via an unspecified manipulation of the archive file format.