# CVE-2026-53266: Linux Kernel Out-of-Bounds Write > A memory corruption vulnerability in the Linux kernel's ebtables SNAT target allows attackers to write to read-only memory, potentially leading to code execution or privilege escalation. - **Severity:** High 8.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`) - **Exploited in the wild:** Yes, since 18 Sep 2026 (CISA KEV) - **Login needed:** Any signed-in user - **Attackable:** Local or same network only - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 25 Jun 2026 - **Updated:** 19 Sep 2026 - **Also known as:** AZL-90563, BELL-CVE-2026-53266, DEBIAN-CVE-2026-53266, GHSA-xmhg-rr34-2chj, RHSA-2026:70797, RHSA-2026:71325, RHSA-2026:73732, ROOT-OS-DEBIAN-11-CVE-2026-53266, ROOT-OS-DEBIAN-12-CVE-2026-53266, ROOT-OS-UBUNTU-2204-CVE-2026-53266, ROOT-OS-UBUNTU-2404-CVE-2026-53266, UBUNTU-CVE-2026-53266 ## What is CVE-2026-53266? CVE-2026-53266 is a high-severity memory corruption vulnerability in Linux kernel, published on 25 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim. ### Official 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(). Weakness: CWE-787 (Out-of-bounds Write) ## Which versions are affected by CVE-2026-53266? It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `bpftool` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `bpftool-debuginfo` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `kernel` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `kernel-abi-stablelists` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `kernel-core` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `kernel-debug` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `kernel-debug-core` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `kernel-debug-debuginfo` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `kernel-debug-devel` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `kernel-debug-modules` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `kernel-debug-modules-extra` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `kernel-debuginfo` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `kernel-debuginfo-common-x86_64` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `kernel-devel` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `kernel-doc` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `kernel-modules` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `kernel-modules-extra` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `kernel-tools` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `kernel-tools-debuginfo` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `kernel-tools-libs` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `perf` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `perf-debuginfo` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `python3-perf` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `python3-perf-debuginfo` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:4.18.0-372.217.1.el8_6 | | `bpftool` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:4.18.0-477.169.1.el8_8 | | `bpftool-debuginfo` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:4.18.0-477.169.1.el8_8 | | `kernel` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:4.18.0-477.169.1.el8_8 | | `kernel-abi-stablelists` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:4.18.0-477.169.1.el8_8 | | `kernel-core` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:4.18.0-477.169.1.el8_8 | | `kernel-debug` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:4.18.0-477.169.1.el8_8 | | `kernel-debug-core` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:4.18.0-477.169.1.el8_8 | | `kernel-debug-debuginfo` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:4.18.0-477.169.1.el8_8 | | `kernel-debug-devel` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:4.18.0-477.169.1.el8_8 | | `kernel-debug-modules` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:4.18.0-477.169.1.el8_8 | | `kernel-debug-modules-extra` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:4.18.0-477.169.1.el8_8 | | `kernel-debuginfo` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:4.18.0-477.169.1.el8_8 | | `kernel-debuginfo-common-ppc64le` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:4.18.0-477.169.1.el8_8 | | `kernel-debuginfo-common-x86_64` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:4.18.0-477.169.1.el8_8 | | `kernel-devel` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:4.18.0-477.169.1.el8_8 | | `kernel-doc` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:4.18.0-477.169.1.el8_8 | Products: Linux kernel. ## How do I fix CVE-2026-53266? Apply the vendor's patch. US federal agencies must fix it by 21 Sep 2026. ## Is CVE-2026-53266 being exploited? Yes. Attackers have exploited CVE-2026-53266 in the wild since at least 18 Sep 2026. Public exploit code: - Tracking CVE-2026-53266, the Linux kernel ebtables SNAT ARP-rewrite page-cache write (github_poc): https://github.com/suominen/CVE-2026-53266 ## Other vulnerabilities in Linux kernel - [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild) - [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild) - [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild) - [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild) - [CVE-2026-46300](https://insights.sbomify.com/CVE-2026-46300/): Linux Kernel Missing Initialization of a Variable (high 7.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-53266 and fix it if it is affected. What it is: CVE-2026-53266 is a high-severity memory corruption vulnerability in Linux kernel, published on 25 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim. Exploitation: Yes. Attackers have exploited CVE-2026-53266 in the wild since at least 18 Sep 2026. Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-53266/ (Markdown: https://insights.sbomify.com/CVE-2026-53266/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53266 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53266 - OSV: https://osv.dev/vulnerability/CVE-2026-53266 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-53266/ Summaries are generated and may contain mistakes; the official description above is the record.