CVE-2026-53266
netfilter: bridge: make ebt_snat ARP rewrite writable
- Published
- Updated
- Reserved
- Assigned by
- Linux
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().
Exploited in the wild
CISA lists this vulnerability in its Known Exploited Vulnerabilities catalog as Linux Kernel Out-of-Bounds Write Vulnerability.
- Added
- 18 Sept 2026
- Fix due (US federal)
- 21 Sept 2026
- Used by ransomware
- Not known
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.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: it is being exploited.
Timeline
ID reserved
By Linux
- 16 days later
· 16 days later
Published
- 3 months later
· 3 months later
Added to CISA KEV
Known exploited in the wild
- 1 day later
· 1 day later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High8.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |
| NVDNVD · Analyzed | 3.1 | High8.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.93% · top 39% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: active · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.8.
Weakness
Affected products
- affected 63137bc5882a1882c553d389fdeeeace86ee1741 – < bf84ad7c7a9ede46e31afaa41a1ba06a159e8c87
- affected 63137bc5882a1882c553d389fdeeeace86ee1741 – < 76280b78cc9f23bdc6438e10ad6dff148ef8375b
- affected 63137bc5882a1882c553d389fdeeeace86ee1741 – < b7e91939ba9be805a62a257fa4e227dffbb88fa0
- affected 63137bc5882a1882c553d389fdeeeace86ee1741 – < afd64b59c3de9bbbdd3759e834fdc55cda716e0b
- affected 63137bc5882a1882c553d389fdeeeace86ee1741 – < 153ea96c806aea395daba907a4f88480b6ad5093
- affected 63137bc5882a1882c553d389fdeeeace86ee1741 – < b18675263db1147c8e1cab625400c13a0d87bd2d
- affected 63137bc5882a1882c553d389fdeeeace86ee1741 – < c9b5ff59feffb92a147a84a5aa28acd2cb8ff4c5
- affected 63137bc5882a1882c553d389fdeeeace86ee1741 – < 67ba971ae02514d85818fe0c32549ab4bfa3bf49
- affected 2f3839075a5f8dcf116c1abe35b36b018ac62445
- affected 51ba2945a8ef65ae437c8f9ba05f0343aa82ae5b
- affected b7d23c2c87584eb429f115c078ed511be8b18e29
- affected 5.4.73 – < 5.5
- affected 5.8.17 – < 5.9
- affected 5.9.2 – < 5.10
- affected 5.10
- unaffected < 5.10
- unaffected 5.10.259 – ≤ 5.10.*
- unaffected 5.15.210 – ≤ 5.15.*
- unaffected 6.1.176 – ≤ 6.1.*
- unaffected 6.6.143 – ≤ 6.6.*
- unaffected 6.12.94 – ≤ 6.12.*
- unaffected 6.18.36 – ≤ 6.18.*
- unaffected 7.0.13 – ≤ 7.0.*
- unaffected 7.1 – ≤ *
References (9)
- https://git.kernel.org/stable/c/bf84ad7c7a9ede46e31afaa41a1ba06a159e8c87 (opens in a new tab)
- https://git.kernel.org/stable/c/76280b78cc9f23bdc6438e10ad6dff148ef8375b (opens in a new tab)
- https://git.kernel.org/stable/c/b7e91939ba9be805a62a257fa4e227dffbb88fa0 (opens in a new tab)
- https://git.kernel.org/stable/c/afd64b59c3de9bbbdd3759e834fdc55cda716e0b (opens in a new tab)
- https://git.kernel.org/stable/c/153ea96c806aea395daba907a4f88480b6ad5093 (opens in a new tab)
- https://git.kernel.org/stable/c/b18675263db1147c8e1cab625400c13a0d87bd2d (opens in a new tab)
- https://git.kernel.org/stable/c/c9b5ff59feffb92a147a84a5aa28acd2cb8ff4c5 (opens in a new tab)
- https://git.kernel.org/stable/c/67ba971ae02514d85818fe0c32549ab4bfa3bf49 (opens in a new tab)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-53266 (opens in a new tab)government-resource
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- CISA KEV catalog (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-53266)Record last updated .