CISA added a Linux Kernel missing initialization of a variable vulnerability to its Known Exploited Vulnerabilities catalog on 2026-10-28, noting it is actively exploited. The flaw could allow for unintended modification of page-cache-backed data via failure to preserve the shared-fragment marker during socket buffer coalescing, causing ESP input processing to decrypt shared fragments in place. It can be chained with CVE-2026-109618 and CVE-2026-109619 to implant PHP webshells and run commands as root. 1