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CVE-2026-53266

netfilter: bridge: make ebt_snat ARP rewrite writable

CVSS 3.1 High 8.8Known exploited (CISA KEV)

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

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().

Official description from the CVE record, published by Linux. Copyright © 1999-2026 The MITRE Corporation. See /security/cve/legal for the CVE license. View the record on cve.org

Key data

CVSS 3.1 High 8.8

Score published by Linux in the CVE record.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

  • Attack vector: Local

    The attacker needs local access to the system, or to trick a user into running something.

  • Attack complexity: Low

    No special conditions are needed. The attack can be repeated at will.

  • Privileges required: Low

    A basic user account is needed.

  • User interaction: None

    No action from any user is needed.

  • Scope: Changed

    The impact can reach other components beyond the vulnerable one.

  • Confidentiality impact: High

    Serious or total effect on the secrecy of data.

  • Integrity impact: High

    Serious or total effect on the trustworthiness of data.

  • Availability impact: High

    Serious or total effect on availability.

CVSS is owned and managed by FIRST.Org, Inc. (FIRST) and is used by permission. Each CVSS score on this site is shown together with its vector string, as published in the CVE record by the source named next to it. Learn more at first.org/cvss.

EPSS

Exploit Prediction Scoring System by FIRST: an estimate of the probability that exploitation activity will be observed in the next 30 days.
Score
0.00934 (0.9% probability)
Percentile
61.1%
Scores of
Nov 10, 2026
Model
v2026.06.15

CISA Known Exploited Vulnerabilities

This CVE is listed in the CISA KEV catalog.
Name in the catalog
Linux Kernel Out-of-Bounds Write Vulnerability
Added to the catalog
Sep 18, 2026
Federal due date
Sep 21, 2026

CISA assessment as of Sep 18, 2026

Stakeholder-Specific Vulnerability Categorization (SSVC) decision points added by CISA.
Exploitation
Recorded by CISA as active
Automatable
no
Technical impact
total

Weakness (CWE)

CWE catalog version 5.0.
CWE names: Copyright © 2006-2026, The MITRE Corporation. See /security/cve/legal for the CWE license.

Affected products

Products listed in the CVE record, as the CNA published them.

  • Linux

    • affected: 63137bc5882a1882c553d389fdeeeace86ee1741 up to before bf84ad7c7a9ede46e31afaa41a1ba06a159e8c87
    • affected: 63137bc5882a1882c553d389fdeeeace86ee1741 up to before 76280b78cc9f23bdc6438e10ad6dff148ef8375b
    • affected: 63137bc5882a1882c553d389fdeeeace86ee1741 up to before b7e91939ba9be805a62a257fa4e227dffbb88fa0
    • affected: 63137bc5882a1882c553d389fdeeeace86ee1741 up to before afd64b59c3de9bbbdd3759e834fdc55cda716e0b
    • affected: 63137bc5882a1882c553d389fdeeeace86ee1741 up to before 153ea96c806aea395daba907a4f88480b6ad5093
    • affected: 63137bc5882a1882c553d389fdeeeace86ee1741 up to before b18675263db1147c8e1cab625400c13a0d87bd2d
    • affected: 63137bc5882a1882c553d389fdeeeace86ee1741 up to before c9b5ff59feffb92a147a84a5aa28acd2cb8ff4c5
    • affected: 63137bc5882a1882c553d389fdeeeace86ee1741 up to before 67ba971ae02514d85818fe0c32549ab4bfa3bf49
    • affected: 2f3839075a5f8dcf116c1abe35b36b018ac62445
    • affected: 51ba2945a8ef65ae437c8f9ba05f0343aa82ae5b
    • affected: b7d23c2c87584eb429f115c078ed511be8b18e29
    • affected: 5.4.73 up to before 5.5
    • affected: 5.8.17 up to before 5.9
    • affected: 5.9.2 up to before 5.10

  • Linux

    • affected: 5.10
    • unaffected: before 5.10
    • unaffected: 5.10.259 up to 5.10.*
    • unaffected: 5.15.210 up to 5.15.*
    • unaffected: 6.1.176 up to 6.1.*
    • unaffected: 6.6.143 up to 6.6.*
    • unaffected: 6.12.94 up to 6.12.*
    • unaffected: 6.18.36 up to 6.18.*
    • unaffected: 7.0.13 up to 7.0.*
    • unaffected: 7.1 up to *

References

Links listed in the CVE record. They lead to other sites, which CubePath does not control.

Timeline

  1. ID reserved
  2. Record published
  3. Added to CISA KEV
  4. Record last updated

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Data from the CVE Program (MITRE), CISA KEV and FIRST EPSS. CVSS is owned by FIRST and used by permission. Not affiliated with or endorsed by MITRE, CISA or FIRST. Data as of Nov 10, 2026, 19:37 UTC. Sources and licenses