DaystoPatch

Linux kernelExploited incident

Linux kernel netfilter ebtables SNAT ARP rewrite out-of-bounds write (CVE-2026-53266)

CVE-2026-53266High, CVSS 8.8In CISA's Known Exploited Vulnerabilities catalog since 18 Sep 2026

  • Exploited after a fix existed
FixedFixed for every supported version on the day it became public.

Response

Silence
0h
First public report to first vendor statement
Exposure
0h
First public report to first fix
Follow-through
0h
First public report to a fix for every supported version
  • Vendor silent
  • Vendor statement, no fix
  • Fixed for some versions
  • Fixed when disclosed
  • Date only, no time of day

Timeline and evidence

Open a moment to see its source and archived quote.

  1. First public report

    CVE-2026-53266 record (CNA: Linux)CuratedQuote verified

    "datePublished":"2026-06-25T08:39:53.190Z"

    CVE title: 'netfilter: bridge: make ebt_snat ARP rewrite writable'.

    Recorded time
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    Curated. Found by a researcher, with a verbatim quote and link.
    Quote check
    Found in the archived copy
    Snapshot
    sha256:03b0be282d8d5f3b…
    Used in metrics
    Yes
    Dispute this timestamp
    5 more sources for this moment
    CVE.org record CVE-2026-53266ClaimedQuote verified25 Jun 2026, 08:39 UTC

    In the Linux kernel, the following vulnerability has been resolved:

    CVE record published.

    Recorded time
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    sha256:03b0be282d8d5f3b…
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    No, kept for the record
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    Bluesky postClaimedQuote not checked yet25 Jun 2026, 09:57 UTC

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

    Earliest third-party post we hold.

    Source
    Bluesky post social
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    Not checked yet
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    No archived snapshot
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    CISA KEV (CVE-2026-53266)ClaimedQuote verified18 Sep 2026

    Linux Kernel Out-of-Bounds Write Vulnerability

    Added to CISA's KEV catalog on 2026-09-18.

    Recorded time
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    Date only (no time of day is shown)
    Origin
    Claimed. The date the source gives.
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    Found in the archived copy
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    sha256:ef8fffede5c47200…
    Used in metrics
    No, kept for the record
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    Mastodon postClaimedQuote not checked yet18 Sep 2026, 15:00 UTC

    🚨 [CISA-2026:0918] CISA Adds 2 Known Exploited Vulnerabilities to Catalog ( https:// secdb.nttzen.cloud/security-ad visory/detail/CISA-2026:0918 ) CISA has added 2 new vulnerabilities to its Known

    Earliest third-party post we hold.

    Source
    Mastodon post social
    Recorded time
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    Claimed. The date the source gives.
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    Not checked yet
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    No archived snapshot
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    Hacker NewsClaimedQuote not checked yet24 Sep 2026, 16:56 UTC

    CISA active Linux kernel CVEs (CVE-2025-39964, CVE-2026-53266, CVE-2025-39682)

    Earliest third-party post we hold.

    Source
    Hacker News hn
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    Claimed. The date the source gives.
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    Not checked yet
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    No archived snapshot
    Used in metrics
    No, kept for the record
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  2. Vendor statement

    at disclosure

    CVE-2026-53266 record (CNA: Linux)CuratedQuote verified

    "datePublished":"2026-06-25T08:39:53.190Z"

    Recorded time
    Precision
    To the minute
    Origin
    Curated. Found by a researcher, with a verbatim quote and link.
    Quote check
    Found in the archived copy
    Snapshot
    sha256:03b0be282d8d5f3b…
    Used in metrics
    Yes
    Dispute this timestamp

  3. First workaround

    No official mitigation found yet.

  4. First fix

    at disclosure

    kernel.org ChangeLog-7.1CuratedQuote verified

    Date: Sun Jun 14 15:58:38 2026 +0100

    Top entry of the Linux 7.1 ChangeLog is the release commit 'Linux 7.1' dated Sun Jun 14 15:58:38 2026 +0100 = 2026-06-14 14:58 UTC (commit author date). Mainline 7.1 is the first listed fixed release.

    Source
    kernel.org ChangeLog-7.1 vendor github
    Recorded time
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    To the minute
    Origin
    Curated. Found by a researcher, with a verbatim quote and link.
    Quote check
    Found in the archived copy
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    sha256:b92023ce223af3f8…
    Used in metrics
    Yes
    Dispute this timestamp

  5. Fixed for all versions

    at disclosure

    kernel.org ChangeLog-7.0.13CuratedQuote verified

    Date: Fri Jun 19 13:48:13 2026 +0200

    Top entry of the Linux 7.0.13 ChangeLog is the release commit 'Linux 7.0.13' dated Fri Jun 19 13:48:13 2026 +0200 = 2026-06-19 11:48 UTC (commit author date). The stable backports (5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, 6.18.36, 7.0.13) were all tagged on 2026-06-19; 7.0.13 was the last.

    Source
    kernel.org ChangeLog-7.0.13 vendor github
    Recorded time
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    To the minute
    Origin
    Curated. Found by a researcher, with a verbatim quote and link.
    Quote check
    Found in the archived copy
    Snapshot
    sha256:12c40bd84fda3129…
    Used in metrics
    Yes
    Dispute this timestamp

Send this to your boss

No brief for this incident yet. We write one for every open incident and every critical bug exploited before a fix.

Affected products

  • Linux kernel 5.10 up to 5.10.258, 5.15.209, 6.1.175, 6.6.142, 6.12.93, 6.18.35, 7.0.12 (netfilter: bridge ebt_snat)
How we built this timeline

Kernel moment model: vendor/world = the kernel CNA's CVE publication (first security-labelled public signal); First fix = first stable or mainline release containing the fix (R2: counts even though it precedes the CVE);

Fixed for all versions = the last of the stable/LTS releases the CVE record lists as fixed (R6: provided every then-supported affected line is listed). Release dates come from kernel.org ChangeLog files.

The fix is normally public in stable releases before the CVE is published, so exposure is zero. Downstream lag (Android, distributions) is not graded here.

The record also marks backport-introduced exposure in 5.4.73+, 5.8.17+ and 5.9.2+ (branches end-of-life by 2026). No public report of exploitation before the fixes;

KEV 18 Sep 2026 (see linux-kernel-cve-2025-39964 notes on the shared KEV date). CVSS 8.8 from the kernel CNA record.

Related

Linux kernel report card