CVE-2026-49494 – Comodo Internet Security Inspect.sys IPv6 Integer Underflow Remote Denial of Service

CVE ID :CVE-2026-49494

Published : June 7, 2026, 12:08 p.m. | 24 minutes ago

Description :Comodo Internet Security’s firewall driver Inspect.sys contains an integer underflow in its IPv6 packet parser. The parser decrements an unsigned 64-bit payload-length value (taken from the IPv6 fixed header’s payload length field) by the size of each IPv6 extension header without validating it, so a packet whose declared payload length is smaller than the sum of its extension-header lengths underflows the value to a near-maximal 64-bit integer. Because IPv6 parsing occurs before firewall rule enforcement, a remote, unauthenticated attacker can send a single crafted IPv6 packet – even to a host with all ports blocked – to trigger an out-of-bounds read (and, on a separate code path, an oversized memcpy) in the Windows kernel at DISPATCH_LEVEL, crashing the system (BSOD).

Severity: 8.7 | HIGH

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