CVE-2026-49494
📛 CVE Title
(no title)
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).
Description (MITRE) cveawg.mitre.org
Pulled from cveawg.mitre.org/api/cve/CVE-2026-49494 on 2026-06-30. Shown when MITRE's text differs from the cvelistV5 mirror.
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 DISPATCH_LEVEL, resulting in a blue screen of death even on hosts with all ports blocked.
Overview
- State
- —
- Assigner (CNA)
- —
- CVSS severity
- high
- CVSS score
- 7.5 / 10
- CVSS vector
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Effective score
- 7.5 / 10 HIGH source: CNA overview
- CWE(s)
- —
- Reserved
- —
- Published
- —
- Last updated
- —
- Source
- https://www.tenable.com/cve/CVE-2026-49494
- Linked Threat
- CVE-2026-49494 — CVE-2026-49494
NVD triage scoring NVD CVE 2.0
Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.
- NVD published
- 2026-06-07 13:16:20 UTC
- NVD last modified
- 2026-06-23 15:16:35 UTC
- NVD CVSS v3.1
- 7.5 / 10 HIGH source: disclosure@vulncheck.com
- NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Exploitability subscore
- 3.9 / 10
- Impact subscore
- 3.6 / 10
- EPSS score
- 0.0054 (probability of exploitation in next 30 days)
- EPSS percentile
- 41.39% vs all CVEs — higher = more likely to be exploited, as of 2026-06-30
NVD-assigned CWE(s):
CWE-191
(differs from the CNA list above)
NVD / KEV / EPSS data refreshed 2026-06-30 20:08 UTC. Re-run the 🛰 Backfill from NVD button above to refresh.
European Union Vulnerability Database ENISA EUVD
ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.
- EUVD ID
-
EUVD-2026-34990 - Assigner
- VulnCheck
- Published
- Jun 7, 2026, 12:08:59 PM
- Updated
- Jun 23, 2026, 2:07:23 PM
- EUVD base score (CVSS 4.0)
-
8.7 / 10
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 - EUVD-reported EPSS
- 0.5400
- Vendors
- Xcitium, Xcitium (formerly Comodo Security Solutions)
- Products
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Comodo Internet Security (0 ≤12.3.4.8162)Xcitium Client Security (XCS) (0 <13.8.2.10019)
- Aliases
-
GHSA-87cf-mxjw-fmjh
ENISA description: 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 DISPATCH_LEVEL, resulting in a blue screen of death even on hosts with all ports blocked.
EUVD references (4)
Vendor references (0)
References embedded in the original CVE record by the assigning CNA.
None in the CVE record.
MITRE references (2) cveawg.mitre.org
Pulled from MITRE's CVE Services API by the 🛰 Backfill from MITRE button.
- Xcitium Release Notes release-notes, patch
- VulnCheck Advisory: Comodo Internet Security Inspect.sys IPv6 Integer Underflow Remote Denial of Service third-party-advisory
Web references (6)
DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.
- https://nvd.nist.gov/vuln/detail/CVE-2026-49494 tenable:nvd.nist.gov
- https://github.com/MalwareTech/ComoDoS tenable:github.com
- https://www.first.org/epss/ tenable:www.first.org
- https://www.vulncheck.com/advisories/comodo-internet-security-inspect-sys-ipv6-integer-underflow-remote-denial-of-service tenable:www.vulncheck.com
- https://www.cve.org/CVERecord?id=CVE-2026-49494 tenable:www.cve.org
- https://malwaretech.com/2026/06/exploiting-a-remote-kernel-vulnerability-in-comodo-internet-security.html tenable:malwaretech.com
NVD-tagged references (4)
Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.
- https://github.com/MalwareTech/ComoDoS disclosure@vulncheck.com
- https://malwaretech.com/2026/06/exploiting-a-remote-kernel-vulnerability-in-comodo-internet-security.html disclosure@vulncheck.com
- https://updates.xcitium.com/#note11312 disclosure@vulncheck.com
- https://www.vulncheck.com/advisories/xcitium-client-security-comodo-internet-security-remote-dos disclosure@vulncheck.com
Remediations (10)
Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.
-
web:cybersecuritynews.com
Microsoft has officially acknowledged a critical zero-day vulnerability in Microsoft Defender, publicly dubbed "RoguePlanet," and confirmed it is actively developing a security patch to address the flaw.
2026-06-19 02:37 UTC -
web:cybersixt.com
Microsoft released its June 2026 Patch Tuesday updates, addressing 206 security vulnerabilities across Windows and related software, of which three were publicly disclosed zero‑day flaws, including an HTTP/2 bomb vulnerability ( CVE - 2026 -49160). The patches are now available for installation; administrators are advised to apply them promptly to mitigate potential exploitation.
2026-06-19 02:37 UTC -
web:portal.msrc.microsoft.com
The Security Update Guide provides information on the latest Microsoft security updates, helping users understand and address potential vulnerabilities effectively.
2026-06-19 02:37 UTC -
web:www.crowdstrike.com
Microsoft's March 2026 Patch Tuesday addresses 82 CVEs , featuring eight Critical vulnerabilities.
2026-06-19 02:37 UTC -
web:www.crowdstrike.com
Microsoft has released security updates for 130 vulnerabilities, including 30 critical, in its May 2026 Patch Tuesday rollout.
2026-06-19 02:37 UTC -
web:www.malwarebytes.com
Microsoft says it's working on a fix for an unpatched Defender vulnerability that can give attackers the highest level of access on Windows.
2026-06-19 02:37 UTC -
web:www.microsoft.com
Security Update Guide Notifications Microsoft's free Security Update Guide Notifications provide links to security-related software updates and notification of re-released security updates. These notifications are sent via email throughout the month as needed.
2026-06-19 02:37 UTC -
web:www.oracle.com
This Critical Patch Update contains 481 new security patches across the product families listed below. Please note that an MOS note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at April 2026 Critical Patch Update: Executive Summary and Analysis.
2026-06-19 02:37 UTC -
web:www.oracle.com
This Critical Security Patch Update contains 35 new security patches across the product families listed below. Please note that an MOS note summarizing the content of this Critical Security Patch Update and other Oracle Software Security Assurance activities is located at May 2026 Critical Security Patch Update: Executive Summary and Analysis.
2026-06-19 02:37 UTC -
web:zecurit.com
Get the complete breakdown of Microsoft's June 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .
2026-06-19 02:37 UTC
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