Critical SEVERITY — Vulnerability

CVE-2026-53266 — Linux Kernel Out-of-Bounds Write Vulnerability

Linux Kernel contains an out-of-bounds write vulnerability in the ebtables SNAT target which allows an ARP sender hardware address rewrite to write directly into a nonlinear socket-buffer fragment backed by a splice-imported file page. The impacted product(s) could be end-of-life (EoL) and/or end-of-service (EoS). Users are advised to discontinue use and/or transition to a supported version.

Platform
Ubuntu Server
CVE Record
CVE-2026-53266
Advisory
CISA-KEV
Published
18 September 2026
Views
18
Primary source: Review the official advisory at nvd.nist.gov Go to Source

Status

This vulnerability appears in CISA's catalog of known exploited vulnerabilities. It is not a theoretical risk — it is being used in the wild.

Description

Linux Kernel contains an out-of-bounds write vulnerability in the ebtables SNAT target which allows an ARP sender hardware address rewrite to write directly into a nonlinear socket-buffer fragment backed by a splice-imported file page. The impacted product(s) could be end-of-life (EoL) and/or end-of-service (EoS). Users are advised to discontinue use and/or transition to a supported version.

Details

  • Vendor: Linux
  • Product: Kernel
  • Added to catalog: 2026-09-18

Action Required by CISA

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

  • Due date for federal agencies: 2026-09-21
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