# CVE-2026-53266: netfilter: bridge: make ebt_snat ARP rewrite writable

> CVE-2026-53266: netfilter: bridge: make ebt_snat ARP rewrite writable. CVSS 8.8 (CVSS 3.1), in CISA KEV.

Canonical: https://rewindex.com/cve/CVE-2026-53266
Last updated: 2026-09-19T04:17:53Z

- Published: 2026-06-25 08:39 UTC · Updated: 2026-09-19 04:17 UTC · Assigner: Linux
- CVSS: 8.8 (CVSS 3.1) · Severity: High · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- EPSS: 0.93%, 61th percentile (scored 2026-10-25)
- CISA KEV: yes, added 2026-09-18, federal due date 2026-09-21, ransomware use: Unknown

## Description

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().

## CISA required action

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.

## Affected vendors and products

- Linux: Linux

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-53266)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-53266)
- [https://git.kernel.org/stable/c/153ea96c806aea395daba907a4f88480b6ad5093](https://git.kernel.org/stable/c/153ea96c806aea395daba907a4f88480b6ad5093)
- [https://git.kernel.org/stable/c/67ba971ae02514d85818fe0c32549ab4bfa3bf49](https://git.kernel.org/stable/c/67ba971ae02514d85818fe0c32549ab4bfa3bf49)
- [https://git.kernel.org/stable/c/76280b78cc9f23bdc6438e10ad6dff148ef8375b](https://git.kernel.org/stable/c/76280b78cc9f23bdc6438e10ad6dff148ef8375b)
- [https://git.kernel.org/stable/c/afd64b59c3de9bbbdd3759e834fdc55cda716e0b](https://git.kernel.org/stable/c/afd64b59c3de9bbbdd3759e834fdc55cda716e0b)
- [https://git.kernel.org/stable/c/b18675263db1147c8e1cab625400c13a0d87bd2d](https://git.kernel.org/stable/c/b18675263db1147c8e1cab625400c13a0d87bd2d)
- [https://git.kernel.org/stable/c/b7e91939ba9be805a62a257fa4e227dffbb88fa0](https://git.kernel.org/stable/c/b7e91939ba9be805a62a257fa4e227dffbb88fa0)
- [https://git.kernel.org/stable/c/bf84ad7c7a9ede46e31afaa41a1ba06a159e8c87](https://git.kernel.org/stable/c/bf84ad7c7a9ede46e31afaa41a1ba06a159e8c87)
- [https://git.kernel.org/stable/c/c9b5ff59feffb92a147a84a5aa28acd2cb8ff4c5](https://git.kernel.org/stable/c/c9b5ff59feffb92a147a84a5aa28acd2cb8ff4c5)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-53266 · Markdown: https://rewindex.com/cve/CVE-2026-53266.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-53266 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T03:10:52.926Z