Risk Letters

Exploited vulnerability

CVE-2026-46300

TLP:CLEAR

Linux Kernel Missing Initialization of a Variable Vulnerability

Linux Kernel contains a missing initialization of a variable vulnerability that 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. This vulnerability can be chained with CVE-2026-109618 and CVE-2026-109619 to implant PHP webshells and run commands as root.

Facts

  • Vendor: Linux
  • Product: Kernel
  • CVSS: 7.8
  • EPSS (probability of exploitation within 30 days): 16.1 %
  • On CISA's Known Exploited Vulnerabilities list since: 28 October 2026
  • First known exploitation: 28 October 2026
  • CISA's deadline for US federal agencies: 31 October 2026
  • Weakness: CWE-456
  • First seen by Risk Letters: 28 October 2026

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Data: NVD (public domain), CISA KEV, FIRST EPSS, MITRE ATT&CK, AlienVault OTX. NVD