Vulnerability details
CVE-2026-49494
Xcitium Client SecurityXcitium (formerly Comodo Security Solutions) Comodo Internet Security
Xcitium Client Security / Comodo Internet Security Remote Denial of Service
CVSS 4.0
8.7High
Official 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.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 8.7High | 4.0 | CVEProject cvelistV5 (CNA) (VulnCheck) | 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 |
| 7.5High | 3.1 | CVEProject cvelistV5 (CNA) (VulnCheck) | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| Xcitium | Xcitium Client Security (XCS) | v < 13.8.2.10019 | CVEProject cvelistV5 (CNA) |
| Xcitium (formerly Comodo Security Solutions) | Comodo Internet Security | v ≤ 12.3.4.8162 | CVEProject cvelistV5 (CNA) |
References and advisories
4- https://malwaretech.com/2026/06/exploiting-a-remote-kernel-vulnerability-in-comodo-internet-security.html technical-descriptionexploit
- https://github.com/MalwareTech/ComoDoS exploit
- https://updates.xcitium.com/#note11312 release-notespatch
- https://www.vulncheck.com/advisories/xcitium-client-security-comodo-internet-security-remote-dos third-party-advisory
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Details
- Published
- 2026-06-07
- Last updated
- 2026-06-23
- State
- Published
- Assigner (CNA)
- VulnCheck
Exploit prediction (EPSS)
0.54%
Probability of exploitation in 30 days
45.7%
Percentile (among all CVEs)
SSVC assessment (CISA)
- Automatable
- Yes
- Exploitation
- Proof of concept
- Technical impact
- Partial
Weaknesses (CWE)
- CWE-191Integer Underflow (Wrap or Wraparound)