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Known Exploited Vulnerability
8.8
HIGH CVSS 3.1
CVE-2026-53266
Linux Kernel Out-of-Bounds Write Vulnerability - [Actively Exploited]
Overview
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().

Details
INFO

Published Date :

June 25, 2026, 9:16 a.m.

Last Modified :

Sept. 19, 2026, 4:17 a.m.

Remotely Exploit :

No

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
CISA Notification
CISA KEV (Known Exploited Vulnerabilities)

For the benefit of the cybersecurity community and network defenders—and to help every organization better manage vulnerabilities and keep pace with threat activity—CISA maintains the authoritative source of vulnerabilities that have been exploited in the wild.

Description :

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.

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.

Known Ransomware Campaign Use:

Unknown

Notes :

This vulnerability affects an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: ; https://git.kernel.org/stable/c/bf84ad7c7a9ede46e31afaa41a1ba06a159e8c87; https://git.kernel.org/stable/c/76280b78cc9f23bdc6438e10ad6dff148ef8375b; https://git.kernel.org/stable/c/b7e91939ba9be805a62a257fa4e227dffbb88fa0; https://git.kernel.org/stable/c/afd64b59c3de9bbbdd3759e834fdc55cda716e0b; https://git.kernel.org/stable/c/153ea96c806aea395daba907a4f88480b6ad5093; https://git.kernel.org/stable/c/b18675263db1147c8e1cab625400c13a0d87bd2d; https://git.kernel.org/stable/c/c9b5ff59feffb92a147a84a5aa28acd2cb8ff4c5; https://git.kernel.org/stable/c/67ba971ae02514d85818fe0c32549ab4bfa3bf49 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-53266

Impact
Affected Products

The following products are affected by CVE-2026-53266 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
: Total Affected Vendor : 1 | Products : 1
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 134c704f-9b21-4f2e-91b3-4a467353bcc0
CVSS 3.1 HIGH 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
Ensure ARP SHA range is writable before modifying it.
  • Apply the Linux kernel patch for netfilter: bridge.
  • Verify skb_ensure_writable() before ARP header modification.
  • Confirm skb_store_bits() can write to the ARP SHA range.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-53266.

URL Resource
https://git.kernel.org/stable/c/153ea96c806aea395daba907a4f88480b6ad5093 Patch
https://git.kernel.org/stable/c/67ba971ae02514d85818fe0c32549ab4bfa3bf49 Patch
https://git.kernel.org/stable/c/76280b78cc9f23bdc6438e10ad6dff148ef8375b Patch
https://git.kernel.org/stable/c/afd64b59c3de9bbbdd3759e834fdc55cda716e0b Patch
https://git.kernel.org/stable/c/b18675263db1147c8e1cab625400c13a0d87bd2d Patch
https://git.kernel.org/stable/c/b7e91939ba9be805a62a257fa4e227dffbb88fa0 Patch
https://git.kernel.org/stable/c/bf84ad7c7a9ede46e31afaa41a1ba06a159e8c87 Patch
https://git.kernel.org/stable/c/c9b5ff59feffb92a147a84a5aa28acd2cb8ff4c5 Patch
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-53266 US Government Resource
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-53266 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-53266 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-53266 vulnerability anywhere in the article.

  • The Hacker News
CISA Flags Three Linux Kernel Vulnerabilities Exploited in the Wild

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Friday added three security flaws impacting the Linux kernel to its Known Exploited Vulnerabilities (KEV) catalog, citing evidence o ... Read more

Published Date: Sep 19, 2026 (11 hours, 4 minutes ago)
  • TheCyberThrone
CISA KEV Update: Three Linux Kernel Bugs, Acronis Backup and Google Pixel

September 18, 2026 — CISA added three Linux kernel vulnerabilities to its Known Exploited Vulnerabilities (KEV) Catalog. Two additional vulnerabilities affecting Acronis Backup and Google Pixel were a ... Read more

Published Date: Sep 19, 2026 (15 hours, 19 minutes ago)

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-53266 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Sep. 19, 2026

    Action Type Old Value New Value
    Changed SSVC {'id': 'CVE-2026-53266', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'active'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-09-18T14:40:13.592810Z'} {'id': 'CVE-2026-53266', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'active'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-09-18T00:00:00+00:00'}
  • Modified Analysis by [email protected]

    Sep. 18, 2026

    Action Type Old Value New Value
    Added Reference Type CISA-ADP: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-53266 Types: US Government Resource
  • CVE CISA KEV Update by 9119a7d8-5eab-497f-8521-727c672e3725

    Sep. 18, 2026

    Action Type Old Value New Value
    Added Date Added 2026-09-18
    Added Due Date 2026-09-18
    Added Required Action 2026-09-18
    Added Vulnerability Name 2026-09-18
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Sep. 18, 2026

    Action Type Old Value New Value
    Added Reference https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-53266
    Changed SSVC {'id': 'CVE-2026-53266', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-09-18T13:17:28.192271Z'} {'id': 'CVE-2026-53266', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'active'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-09-18T14:40:13.592810Z'}
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Sep. 18, 2026

    Action Type Old Value New Value
    Added CWE CWE-787
    Added SSVC {'id': 'CVE-2026-53266', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-09-18T13:17:28.192271Z'}
  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Sep. 18, 2026

    Action Type Old Value New Value
    Added Reference https://git.kernel.org/stable/c/153ea96c806aea395daba907a4f88480b6ad5093
    Added Reference https://git.kernel.org/stable/c/67ba971ae02514d85818fe0c32549ab4bfa3bf49
    Added Reference https://git.kernel.org/stable/c/76280b78cc9f23bdc6438e10ad6dff148ef8375b
    Added Reference https://git.kernel.org/stable/c/afd64b59c3de9bbbdd3759e834fdc55cda716e0b
    Added Reference https://git.kernel.org/stable/c/b18675263db1147c8e1cab625400c13a0d87bd2d
    Added Reference https://git.kernel.org/stable/c/b7e91939ba9be805a62a257fa4e227dffbb88fa0
    Added Reference https://git.kernel.org/stable/c/bf84ad7c7a9ede46e31afaa41a1ba06a159e8c87
    Added Reference https://git.kernel.org/stable/c/c9b5ff59feffb92a147a84a5aa28acd2cb8ff4c5
    Removed Reference https://git.kernel.org/stable/c/153ea96c806aea395daba907a4f88480b6ad5093
    Removed Reference https://git.kernel.org/stable/c/67ba971ae02514d85818fe0c32549ab4bfa3bf49
    Removed Reference https://git.kernel.org/stable/c/76280b78cc9f23bdc6438e10ad6dff148ef8375b
    Removed Reference https://git.kernel.org/stable/c/afd64b59c3de9bbbdd3759e834fdc55cda716e0b
    Removed Reference https://git.kernel.org/stable/c/b18675263db1147c8e1cab625400c13a0d87bd2d
    Removed Reference https://git.kernel.org/stable/c/b7e91939ba9be805a62a257fa4e227dffbb88fa0
    Removed Reference https://git.kernel.org/stable/c/bf84ad7c7a9ede46e31afaa41a1ba06a159e8c87
    Removed Reference https://git.kernel.org/stable/c/c9b5ff59feffb92a147a84a5aa28acd2cb8ff4c5
    Removed Reference Type https://git.kernel.org/stable/c/153ea96c806aea395daba907a4f88480b6ad5093 Types: Patch
    Removed Reference Type https://git.kernel.org/stable/c/67ba971ae02514d85818fe0c32549ab4bfa3bf49 Types: Patch
    Removed Reference Type https://git.kernel.org/stable/c/76280b78cc9f23bdc6438e10ad6dff148ef8375b Types: Patch
    Removed Reference Type https://git.kernel.org/stable/c/afd64b59c3de9bbbdd3759e834fdc55cda716e0b Types: Patch
    Removed Reference Type https://git.kernel.org/stable/c/b18675263db1147c8e1cab625400c13a0d87bd2d Types: Patch
    Removed Reference Type https://git.kernel.org/stable/c/b7e91939ba9be805a62a257fa4e227dffbb88fa0 Types: Patch
    Removed Reference Type https://git.kernel.org/stable/c/bf84ad7c7a9ede46e31afaa41a1ba06a159e8c87 Types: Patch
    Removed Reference Type https://git.kernel.org/stable/c/c9b5ff59feffb92a147a84a5aa28acd2cb8ff4c5 Types: Patch
  • Initial Analysis by [email protected]

    Jul. 08, 2026

    Action Type Old Value New Value
    Added CWE NVD-CWE-noinfo
    Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.8.17 up to (excluding) 5.9 *cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.16 up to (excluding) 6.1.176 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.143 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.15.210 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.18.36 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.94 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.0.13 *cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc6:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.4.73 up to (excluding) 5.5 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.9.2 up to (excluding) 5.10.259
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/153ea96c806aea395daba907a4f88480b6ad5093 Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/67ba971ae02514d85818fe0c32549ab4bfa3bf49 Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/76280b78cc9f23bdc6438e10ad6dff148ef8375b Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/afd64b59c3de9bbbdd3759e834fdc55cda716e0b Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/b18675263db1147c8e1cab625400c13a0d87bd2d Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/b7e91939ba9be805a62a257fa4e227dffbb88fa0 Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/bf84ad7c7a9ede46e31afaa41a1ba06a159e8c87 Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/c9b5ff59feffb92a147a84a5aa28acd2cb8ff4c5 Types: Patch
  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Jun. 28, 2026

    Action Type Old Value New Value
    Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Jun. 25, 2026

    Action Type Old Value New Value
    Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '63137bc5882a1882c553d389fdeeeace86ee1741', 'lessThan': 'bf84ad7c7a9ede46e31afaa41a1ba06a159e8c87', 'versionType': 'git'}, {'status': 'affected', 'version': '63137bc5882a1882c553d389fdeeeace86ee1741', 'lessThan': '76280b78cc9f23bdc6438e10ad6dff148ef8375b', 'versionType': 'git'}, {'status': 'affected', 'version': '63137bc5882a1882c553d389fdeeeace86ee1741', 'lessThan': 'b7e91939ba9be805a62a257fa4e227dffbb88fa0', 'versionType': 'git'}, {'status': 'affected', 'version': '63137bc5882a1882c553d389fdeeeace86ee1741', 'lessThan': 'afd64b59c3de9bbbdd3759e834fdc55cda716e0b', 'versionType': 'git'}, {'status': 'affected', 'version': '63137bc5882a1882c553d389fdeeeace86ee1741', 'lessThan': '153ea96c806aea395daba907a4f88480b6ad5093', 'versionType': 'git'}, {'status': 'affected', 'version': '63137bc5882a1882c553d389fdeeeace86ee1741', 'lessThan': 'b18675263db1147c8e1cab625400c13a0d87bd2d', 'versionType': 'git'}, {'status': 'affected', 'version': '63137bc5882a1882c553d389fdeeeace86ee1741', 'lessThan': 'c9b5ff59feffb92a147a84a5aa28acd2cb8ff4c5', 'versionType': 'git'}, {'status': 'affected', 'version': '63137bc5882a1882c553d389fdeeeace86ee1741', 'lessThan': '67ba971ae02514d85818fe0c32549ab4bfa3bf49', 'versionType': 'git'}, {'status': 'affected', 'version': '2f3839075a5f8dcf116c1abe35b36b018ac62445', 'versionType': 'git'}, {'status': 'affected', 'version': '51ba2945a8ef65ae437c8f9ba05f0343aa82ae5b', 'versionType': 'git'}, {'status': 'affected', 'version': 'b7d23c2c87584eb429f115c078ed511be8b18e29', 'versionType': 'git'}, {'status': 'affected', 'version': '5.4.73', 'lessThan': '5.5', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.8.17', 'lessThan': '5.9', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.9.2', 'lessThan': '5.10', 'versionType': 'semver'}], 'programFiles': ['net/bridge/netfilter/ebt_snat.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '5.10'}, {'status': 'unaffected', 'version': '0', 'lessThan': '5.10', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.259', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.210', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.176', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.143', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.94', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.36', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.0.13', 'versionType': 'semver', 'lessThanOrEqual': '7.0.*'}, {'status': 'unaffected', 'version': '7.1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/bridge/netfilter/ebt_snat.c'], 'defaultStatus': 'affected'}]
    Added 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().
    Added Reference https://git.kernel.org/stable/c/153ea96c806aea395daba907a4f88480b6ad5093
    Added Reference https://git.kernel.org/stable/c/67ba971ae02514d85818fe0c32549ab4bfa3bf49
    Added Reference https://git.kernel.org/stable/c/76280b78cc9f23bdc6438e10ad6dff148ef8375b
    Added Reference https://git.kernel.org/stable/c/afd64b59c3de9bbbdd3759e834fdc55cda716e0b
    Added Reference https://git.kernel.org/stable/c/b18675263db1147c8e1cab625400c13a0d87bd2d
    Added Reference https://git.kernel.org/stable/c/b7e91939ba9be805a62a257fa4e227dffbb88fa0
    Added Reference https://git.kernel.org/stable/c/bf84ad7c7a9ede46e31afaa41a1ba06a159e8c87
    Added Reference https://git.kernel.org/stable/c/c9b5ff59feffb92a147a84a5aa28acd2cb8ff4c5
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
Base CVSS Score: 8.8
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact