Linux Kernel: ebtables SNAT ARP SHA rewrite writable
CVE-2026-53266 Published on June 25, 2026
netfilter: bridge: make ebt_snat ARP rewrite writable
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().
Known Exploited Vulnerability
This Linux Kernel Out-of-Bounds Write Vulnerability is part of CISA's list of Known Exploited Vulnerabilities. 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.
The following remediation steps are recommended / required by September 21, 2026: 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 applicab
Weakness Type
What is a Memory Corruption Vulnerability?
The software writes data past the end, or before the beginning, of the intended buffer. Typically, this can result in corruption of data, a crash, or code execution. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent write operation then produces undefined or unexpected results.
CVE-2026-53266 has been classified to as a Memory Corruption vulnerability or weakness.
Products Associated with CVE-2026-53266
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Affected Versions
Linux:- Version 63137bc5882a1882c553d389fdeeeace86ee1741 and below bf84ad7c7a9ede46e31afaa41a1ba06a159e8c87 is affected.
- Version 63137bc5882a1882c553d389fdeeeace86ee1741 and below 76280b78cc9f23bdc6438e10ad6dff148ef8375b is affected.
- Version 63137bc5882a1882c553d389fdeeeace86ee1741 and below b7e91939ba9be805a62a257fa4e227dffbb88fa0 is affected.
- Version 63137bc5882a1882c553d389fdeeeace86ee1741 and below afd64b59c3de9bbbdd3759e834fdc55cda716e0b is affected.
- Version 63137bc5882a1882c553d389fdeeeace86ee1741 and below 153ea96c806aea395daba907a4f88480b6ad5093 is affected.
- Version 63137bc5882a1882c553d389fdeeeace86ee1741 and below b18675263db1147c8e1cab625400c13a0d87bd2d is affected.
- Version 63137bc5882a1882c553d389fdeeeace86ee1741 and below c9b5ff59feffb92a147a84a5aa28acd2cb8ff4c5 is affected.
- Version 63137bc5882a1882c553d389fdeeeace86ee1741 and below 67ba971ae02514d85818fe0c32549ab4bfa3bf49 is affected.
- Version 2f3839075a5f8dcf116c1abe35b36b018ac62445 is affected.
- Version 51ba2945a8ef65ae437c8f9ba05f0343aa82ae5b is affected.
- Version b7d23c2c87584eb429f115c078ed511be8b18e29 is affected.
- Version 5.4.73 and below 5.5 is affected.
- Version 5.8.17 and below 5.9 is affected.
- Version 5.9.2 and below 5.10 is affected.
- Version 5.10 is affected.
- Before 5.10 is unaffected.
- Version 5.10.259, <= 5.10.* is unaffected.
- Version 5.15.210, <= 5.15.* is unaffected.
- Version 6.1.176, <= 6.1.* is unaffected.
- Version 6.6.143, <= 6.6.* is unaffected.
- Version 6.12.94, <= 6.12.* is unaffected.
- Version 6.18.36, <= 6.18.* is unaffected.
- Version 7.0.13, <= 7.0.* is unaffected.
- Version 7.1, <= * is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.