--- id: CVE-2026-53266 title: |- 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) summary: |- 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 i… severity: high cvss: 8.8 cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H' cwe: - CWE-787 - CWE-825 vendor: linux product: linux_kernel affected: - 'linux_kernel >= 5.4.73, < 5.5' - 'linux_kernel >= 5.8.17, < 5.9' - 'linux_kernel >= 5.9.2, < 5.10.259' - 'linux_kernel >= 5.11, < 5.15.210' - 'linux_kernel >= 5.16, < 6.1.176' - 'linux_kernel >= 6.2, < 6.6.143' - 'linux_kernel >= 6.7, < 6.12.94' - 'linux_kernel >= 6.13, < 6.18.36' - 'linux_kernel >= 6.19, < 7.0.13' - linux_kernel = 7.1 patched: - linux_kernel 7.0.13 published: '2026-06-25' updated: '2026-09-19' sourceUpdated: '2026-09-19T04:17:53.580' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-53266' references: - url: 'https://git.kernel.org/stable/c/153ea96c806aea395daba907a4f88480b6ad5093' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/67ba971ae02514d85818fe0c32549ab4bfa3bf49' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/76280b78cc9f23bdc6438e10ad6dff148ef8375b' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/afd64b59c3de9bbbdd3759e834fdc55cda716e0b' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/b18675263db1147c8e1cab625400c13a0d87bd2d' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/b7e91939ba9be805a62a257fa4e227dffbb88fa0' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/bf84ad7c7a9ede46e31afaa41a1ba06a159e8c87' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/c9b5ff59feffb92a147a84a5aa28acd2cb8ff4c5' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: >- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-53266 label: 134c704f-9b21-4f2e-91b3-4a467353bcc0 - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53266.json - url: 'https://access.redhat.com/security/cve/CVE-2026-53266' - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2485368' - url: 'https://www.cve.org/CVERecord?id=CVE-2026-53266' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-53266' - url: >- https://lore.kernel.org/linux-cve-announce/2026062517-CVE-2026-53266-6162@gregkh/T/#u - url: 'https://www.cisa.gov/known-exploited-vulnerabilities-catalog' - url: 'https://access.redhat.com/errata/RHSA-2026:36645' - url: 'https://access.redhat.com/errata/RHSA-2026:39083' - url: 'https://access.redhat.com/errata/RHSA-2026:39082' - url: 'https://access.redhat.com/errata/RHSA-2026:71327' - url: 'https://access.redhat.com/errata/RHSA-2026:70797' - url: 'https://access.redhat.com/errata/RHSA-2026:71687' - url: 'https://access.redhat.com/errata/RHSA-2026:71657' - url: 'https://access.redhat.com/errata/RHSA-2026:71326' - url: 'https://access.redhat.com/errata/RHSA-2026:71233' - url: 'https://access.redhat.com/errata/RHSA-2026:71601' - url: 'https://access.redhat.com/errata/RHSA-2026:71569' - url: 'https://access.redhat.com/errata/RHSA-2026:71565' - url: 'https://access.redhat.com/errata/RHSA-2026:71325' - url: 'https://access.redhat.com/errata/RHSA-2026:71606' tags: - nvd - cve.org - in-the-wild - exploit-available - kev - csaf - vex - red-hat exploited: true exploitAvailable: true ssvc: exploitation: active automatable: 'no' technicalImpact: total timestamp: '2026-09-18T14:40:13.592810Z' epss: 0.00645 epssPercentile: 0.48675 kev: true kevDateAdded: '2026-09-18' kevDueDate: '2026-09-21' kevRansomware: false ingestedAt: '2026-09-18T13:41:41.668Z' scores: nvd: 8.8 vendor: 7.5 exploits: github: 2 githubRepos: - 'https://github.com/suominen/CVE-2026-53266' - >- https://github.com/mc493/linux-kernel-zero-day-mitigation-zero-downtime-kernel-defense- checkedAt: '2026-09-25T08:21:02.035Z' --- ## Overview 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(). ## Affected - `linux_kernel >= 5.4.73, < 5.5` - `linux_kernel >= 5.8.17, < 5.9` - `linux_kernel >= 5.9.2, < 5.10.259` - `linux_kernel >= 5.11, < 5.15.210` - `linux_kernel >= 5.16, < 6.1.176` - `linux_kernel >= 6.2, < 6.6.143` - `linux_kernel >= 6.7, < 6.12.94` - `linux_kernel >= 6.13, < 6.18.36` - `linux_kernel >= 6.19, < 7.0.13` - `linux_kernel = 7.1` ## Remediation Upgrade past the affected range: - `linux_kernel 7.0.13` ## Vendor advisories - **RHSA-2026:36645** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9), Red Hat Enterprise Linux Real Time for NFV (v. 9), Red Hat Enterprise Linux Real Time (v. 9) · released 2026-07-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:36645) - **RHSA-2026:39083** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8) · released 2026-07-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:39083) - **RHSA-2026:39082** · Red Hat · fixed in: Red Hat Enterprise Linux NFV (v. 8), Red Hat Enterprise Linux RT (v. 8) · released 2026-07-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:39082) - **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 9, Red Hat Enterprise Linux for NVIDIA 26 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 9, Red Hat Enterprise Linux for NVIDIA 26 · updated 2026-09-25 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53266.json) - **RHSA-2026:71327** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v.9.6), Red Hat Enterprise Linux BaseOS EUS (v.9.6), Red Hat CodeReady Linux Builder EUS (v.9.6), Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6), Red Hat Enterprise Linux Real Time EUS (v.9.6) · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71327) - **RHSA-2026:70797** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS AUS (v.8.6), Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) · released 2026-09-23 · [advisory](https://access.redhat.com/errata/RHSA-2026:70797) - **RHSA-2026:71687** · Red Hat · fixed in: Red Hat Enterprise Linux Server (v. 7 ELS), Red Hat Enterprise Linux Server Optional (v. 7 ELS) · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71687) - **RHSA-2026:71657** · Red Hat · fixed in: Red Hat Enterprise Linux for Real Time (v. 7 ELS) · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71657) - **RHSA-2026:71326** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux BaseOS EUS (v. 10.0), Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0), Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0), Red Hat Enterprise Linux Real Time EUS (v. 10.0) · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71326) - **RHSA-2026:71233** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10), Red Hat Enterprise Linux Real Time for NFV (v. 10), Red Hat Enterprise Linux Real Time (v. 10) · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71233) - **RHSA-2026:71601** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.2), Red Hat Enterprise Linux BaseOS E4S (v.9.2) · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71601) - **RHSA-2026:71569** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.4), Red Hat Enterprise Linux BaseOS E4S (v.9.4), Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4), Red Hat Enterprise Linux Real Time E4S (v.9.4) · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71569) - **RHSA-2026:71565** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS AUS (v.8.4), Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4) · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71565)