CVE Watch19 sept 2026

CVE-2026-53266

Linux Kernel Out-of-Bounds Write Vulnerability

CVSS

8.8

Alto

EPSS

0.8%

p57

KEV

SÍ

18 sept 2026

Exploit Today

0-100

Publicado: 25 jun 2026 · Última mod.: 19 sept 2026 · CWE-787

EPSS · 30d

0.1%EPSS · 30 días0.8%

2026-09-182026-10-15

Ficha del catálogo KEV

Producto

Linux / Kernel

Vulnerabilidad

Linux Kernel Out-of-Bounds Write Vulnerability

Añadido a KEV

18 sept 2026

Remediar antes de

21 sept 2026

Uso conocido en ransomware

Descripción resumida

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.

Acción requerida

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.

Notas

This vulnerability affects an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: ; https://git.kernel.org/stable/c/bf84ad7c7a9ede46e31afaa41a1ba06a159e8c87; https://git.kernel.org/stable/c/76280b78cc9f23bdc6438e10ad6dff148ef8375b; https://git.kernel.org/stable/c/b7e91939ba9be805a62a257fa4e227dffbb88fa0; https://git.kernel.org/stable/c/afd64b59c3de9bbbdd3759e834fdc55cda716e0b; https://git.kernel.org/stable/c/153ea96c806aea395daba907a4f88480b6ad5093; https://git.kernel.org/stable/c/b18675263db1147c8e1cab625400c13a0d87bd2d; https://git.kernel.org/stable/c/c9b5ff59feffb92a147a84a5aa28acd2cb8ff4c5; https://git.kernel.org/stable/c/67ba971ae02514d85818fe0c32549ab4bfa3bf49 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-53266

Descripción técnica

In the Linux kernel, the following vulnerability has been resolved: netfilter: bridge: make ebt_snat ARP rewrite writable The ebtables SNAT target keeps the Ethernet source address rewrite behind skb_ensure_writable(skb, 0). This is intentional: at the bridge ebtables hooks the Ethernet header is addressed through skb_mac_header()/eth_hdr(), while skb->data points at the Ethernet payload. Asking skb_ensure_writable() for ETH_HLEN bytes would check the payload, not the Ethernet header, and would reintroduce the small packet regression fixed by commit 63137bc5882a. However, the optional ARP sender hardware address rewrite is different. It writes through skb_store_bits() at an offset relative to skb->data: skb_store_bits(skb, sizeof(struct arphdr), info->mac, ETH_ALEN) skb_header_pointer() only safely reads the ARP header; it does not make the later sender hardware address range writable. If that range is still held in a nonlinear skb fragment backed by a splice-imported file page, skb_store_bits() maps the frag page and copies the new MAC address directly into it. Ensure the ARP SHA range is writable before reading the ARP header and before calling skb_store_bits().

Referencias oficiales

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