CVE-2026-49494 Xcitium Client Security / Comodo Internet Security Remote Denial of Service
Remote attackers can crash Windows systems via crafted IPv6 packets due to an integer underflow in the firewall driver, affecting Xcitium and Comodo security products.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-49494?
CVE-2026-49494 is a high-severity vulnerability in Xcitium Comodo Internet Security, published on 7 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-191
Which versions are affected by CVE-2026-49494?
How do I fix CVE-2026-49494?
No fix has been published for CVE-2026-49494 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-49494 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-49494 exists.
Sources
Also known as GHSA-87cf-mxjw-fmjh.