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).
Published: 2026-06-07
Score: 8.7 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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History

Sun, 07 Jun 2026 12:30:00 +0000

Type Values Removed Values Added
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).
Title Comodo Internet Security Inspect.sys IPv6 Integer Underflow Remote Denial of Service
First Time appeared Comodo
Comodo internet Security
Weaknesses CWE-191
CPEs cpe:2.3:a:comodo:internet_security:*:*:*:*:*:*:*:*
Vendors & Products Comodo
Comodo internet Security
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Subscriptions

Comodo Internet Security
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-06-07T12:08:59.492Z

Reserved: 2026-05-31T11:54:34.993Z

Link: CVE-2026-49494

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-06-07T13:16:20.927

Modified: 2026-06-07T13:16:20.927

Link: CVE-2026-49494

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses