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NVD / CVE Program· CNA Linux

CVE-2026-53266: netfilter: bridge: make ebt_snat ARP rewrite writable

Noroxi assessment

Priority: This week (action score 65/100)

  • CISA has confirmed exploitation in the wild (Sep 18, 2026). Remediation deadline for US federal agencies: Sep 21, 2026.
  • Probability of exploitation in the next 30 days: 0.93% (FIRST EPSS); higher than 60.8% of all records.
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 153ea96c806aea395daba907a4f88480b6ad5093, 5.10, 5.5; azl3 kernel 6.6.141.1-1 on Azure Linux 3.0 6.6.143.1-1.

Don’t wait for the next maintenance window. Upgrade to Linux Linux 153ea96c806aea395daba907a4f88480b6ad5093, 5.10, 5.5; azl3 kernel 6.6.141.1-1 on Azure Linux 3.0 6.6.143.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · CISA KEV · FIRST EPSS

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().

HighCVSS 8.8 · v3.1KEVWeaponized Fix available
Published
Jun 25, 2026
Updated
Sep 19, 2026
EPSS
0.9% · 60th percentile

Report tools

JSON

Action score

65

This week

Don’t wait for the next maintenance window.

CVSS
35 / 40 · 8.8 / 10
CISA KEV
30 / 30 · Listed
EPSS
0 / 30 · 0.9%

CISA SSVC decision

Exploitation
active
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
8.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Actively exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on Sep 18, 2026. That signals real attacks, not theory.

Remediation deadline for US federal agencies: Sep 21, 2026.

Get told when this record changes

  • In CISA KEV: exploitation in the wild confirmed
  • Weaponized exploit exists
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.4.73 and later · before 5.5
  • linux linux kernel5.8.17 and later · before 5.9
  • linux linux kernel5.9.2 and later · before 5.10.259
  • linux linux kernel5.11 and later · before 5.15.210
  • linux linux kernel5.16 and later · before 6.1.176
  • linux linux kernel6.2 and later · before 6.6.143
  • linux linux kernel6.7 and later · before 6.12.94
  • linux linux kernel6.13 and later · before 6.18.36
  • linux linux kernel6.19 and later · before 7.0.13
  • linux linux kernel7.1

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 2f3839075a5f8dcf116c1abe35b36b018ac62445, 51ba2945a8ef65ae437c8f9ba05f0343aa82ae5b, b7d23c2c87584eb429f115c078ed511be8b18e29, 5.10affected
    • 63137bc5882a1882c553d389fdeeeace86ee1741 and later · before bf84ad7c7a9ede46e31afaa41a1ba06a159e8c87affected · git
    • 63137bc5882a1882c553d389fdeeeace86ee1741 and later · before 76280b78cc9f23bdc6438e10ad6dff148ef8375baffected · git
    • 63137bc5882a1882c553d389fdeeeace86ee1741 and later · before b7e91939ba9be805a62a257fa4e227dffbb88fa0affected · git
    • 63137bc5882a1882c553d389fdeeeace86ee1741 and later · before afd64b59c3de9bbbdd3759e834fdc55cda716e0baffected · git
    • 63137bc5882a1882c553d389fdeeeace86ee1741 and later · before 153ea96c806aea395daba907a4f88480b6ad5093affected · git
    • 63137bc5882a1882c553d389fdeeeace86ee1741 and later · before b18675263db1147c8e1cab625400c13a0d87bd2daffected · git
    • 63137bc5882a1882c553d389fdeeeace86ee1741 and later · before c9b5ff59feffb92a147a84a5aa28acd2cb8ff4c5affected · git
    • 63137bc5882a1882c553d389fdeeeace86ee1741 and later · before 67ba971ae02514d85818fe0c32549ab4bfa3bf49affected · git
    • 5.4.73 and later · before 5.5affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10kernel-64k-debug-develbefore 6.12.0-211.59.1.el10_26.12.0-211.59.1.el10_2
AlmaLinux:10kernel-64k-debug-devel-matchedbefore 6.12.0-211.59.1.el10_26.12.0-211.59.1.el10_2
AlmaLinux:10kernel-64k-develbefore 6.12.0-211.59.1.el10_26.12.0-211.59.1.el10_2
AlmaLinux:10kernel-64k-devel-matchedbefore 6.12.0-211.59.1.el10_26.12.0-211.59.1.el10_2
AlmaLinux:10kernel-debug-develbefore 6.12.0-211.59.1.el10_26.12.0-211.59.1.el10_2
AlmaLinux:10kernel-debug-devel-matchedbefore 6.12.0-211.59.1.el10_26.12.0-211.59.1.el10_2
AlmaLinux:10kernel-develbefore 6.12.0-211.59.1.el10_26.12.0-211.59.1.el10_2
AlmaLinux:10kernel-devel-matchedbefore 6.12.0-211.59.1.el10_26.12.0-211.59.1.el10_2
AlmaLinux:10kernel-docbefore 6.12.0-211.59.1.el10_26.12.0-211.59.1.el10_2
AlmaLinux:10kernel-headersbefore 6.12.0-211.59.1.el10_26.12.0-211.59.1.el10_2
AlmaLinux:10kernel-zfcpdump-develbefore 6.12.0-211.59.1.el10_26.12.0-211.59.1.el10_2
AlmaLinux:10kernel-zfcpdump-devel-matchedbefore 6.12.0-211.59.1.el10_26.12.0-211.59.1.el10_2
AlmaLinux:10perfbefore 6.12.0-211.59.1.el10_26.12.0-211.59.1.el10_2
AlmaLinux:10python3-perfbefore 6.12.0-211.59.1.el10_26.12.0-211.59.1.el10_2
AlmaLinux:8bpftoolbefore 4.18.0-553.143.1.el8_104.18.0-553.143.1.el8_10
AlmaLinux:8kernelbefore 4.18.0-553.143.1.el8_104.18.0-553.143.1.el8_10
AlmaLinux:8kernel-abi-stablelistsbefore 4.18.0-553.143.1.el8_104.18.0-553.143.1.el8_10
AlmaLinux:8kernel-corebefore 4.18.0-553.143.1.el8_104.18.0-553.143.1.el8_10
AlmaLinux:8kernel-cross-headersbefore 4.18.0-553.143.1.el8_104.18.0-553.143.1.el8_10
AlmaLinux:8kernel-debugbefore 4.18.0-553.143.1.el8_104.18.0-553.143.1.el8_10
AlmaLinux:8kernel-debug-corebefore 4.18.0-553.143.1.el8_104.18.0-553.143.1.el8_10
AlmaLinux:8kernel-debug-develbefore 4.18.0-553.143.1.el8_104.18.0-553.143.1.el8_10
AlmaLinux:8kernel-debug-modulesbefore 4.18.0-553.143.1.el8_104.18.0-553.143.1.el8_10
AlmaLinux:8kernel-debug-modules-extrabefore 4.18.0-553.143.1.el8_104.18.0-553.143.1.el8_10

+96

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-53259Jun 25, 2026 · ipv6: anycast: insert aca into global hash under idev->lock
    31Monitor
  • ← EarlierCVE-2026-53261Jun 25, 2026 · devlink: Release nested relation on devlink free
    22Monitor
  • Later →CVE-2026-53271Jun 25, 2026 · ksmbd: fix NULL-deref of opinfo->conn in oplock/lease break notifiers
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux153ea96c806aea395daba907a4f88480b6ad5093Vendor (CNA)
Linux Linux5.10Vendor (CNA)
Linux Linux5.5Vendor (CNA)
Linux Linux5.9Vendor (CNA)
Linux Linux67ba971ae02514d85818fe0c32549ab4bfa3bf49Vendor (CNA)
Linux Linux76280b78cc9f23bdc6438e10ad6dff148ef8375bVendor (CNA)
Linux Linuxafd64b59c3de9bbbdd3759e834fdc55cda716e0bVendor (CNA)
Linux Linuxb18675263db1147c8e1cab625400c13a0d87bd2dVendor (CNA)
Linux Linuxb7e91939ba9be805a62a257fa4e227dffbb88fa0Vendor (CNA)
Linux Linuxbf84ad7c7a9ede46e31afaa41a1ba06a159e8c87Vendor (CNA)
Linux Linuxc9b5ff59feffb92a147a84a5aa28acd2cb8ff4c5Vendor (CNA)
azl3 kernel 6.6.141.1-1 on Azure Linux 3.06.6.143.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:kernel5.14.0-687.23.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k5.14.0-687.23.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-core5.14.0-687.23.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug5.14.0-687.23.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-core5.14.0-687.23.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel5.14.0-687.23.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched5.14.0-687.23.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules5.14.0-687.23.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-core5.14.0-687.23.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra5.14.0-687.23.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-devel5.14.0-687.23.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-devel-matched5.14.0-687.23.1.el9_8 · AlmaLinux:9Package registry (OSV)
debian:linux6.1.176-1 · Debian:12Package registry (OSV)
red hat:kernel-64k-debug-debuginfo0:5.14.0-687.23.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-64k-debug-devel0:5.14.0-687.23.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-64k-debug-devel-matched0:5.14.0-687.23.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-64k-debuginfo0:5.14.0-687.23.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-64k-devel0:5.14.0-687.23.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)

+20

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

  • Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHubstars:02026-09-20

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. CISA KEV+85 d
  3. First PoC+87 d
  4. TodayNov 6, 2026+135 d

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Changed
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-787 · Out-of-bounds Write

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (8 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records