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CVE-2026-46300

net: skbuff: preserve shared-frag marker during coalescing

CVSS 3.1 High 7.8Known exploited (CISA KEV)

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

Description

In the Linux kernel, the following vulnerability has been resolved: net: skbuff: preserve shared-frag marker during coalescing skb_try_coalesce() can attach paged frags from @from to @to. If @from has SKBFL_SHARED_FRAG set, the resulting @to skb can contain the same externally-owned or page-cache-backed frags, but the shared-frag marker is currently lost. That breaks the invariant relied on by later in-place writers. In particular, ESP input checks skb_has_shared_frag() before deciding whether an uncloned nonlinear skb can skip skb_cow_data(). If TCP receive coalescing has moved shared frags into an unmarked skb, ESP can see skb_has_shared_frag() as false and decrypt in place over page-cache backed frags. Propagate SKBFL_SHARED_FRAG when skb_try_coalesce() transfers paged frags. The tailroom copy path does not need the marker because it copies bytes into @to's linear data rather than transferring frag descriptors.

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 7.8

Score published by Linux in the CVE record.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/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: Unchanged

    The impact stays within the vulnerable component.

  • 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 3.1 High 7.8

Score published by redhat-SADP in the CVE record.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/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: Unchanged

    The impact stays within the vulnerable component.

  • 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
0.16130 (16.1% probability)
Percentile
97.0%
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 Missing Initialization of a Variable Vulnerability
Added to the catalog
Oct 28, 2026
Federal due date
Oct 31, 2026

CISA assessment as of May 14, 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.
  • CWE-123Write-what-where Condition
  • CWE-456Missing Initialization of a Variable

Affected products

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

  • Linux

    • affected: cef401de7be8c4e155c6746bfccf721a4fa5fab9 up to before 3599e6b3cc1ada96883d496a50a210d3afbb6987
    • affected: cef401de7be8c4e155c6746bfccf721a4fa5fab9 up to before 2f2b16022a2e10ca7bccfb98db5ed2ec0f72641c
    • affected: cef401de7be8c4e155c6746bfccf721a4fa5fab9 up to before 9d3e5fd19fe1063bf607219e8562fbd567b8e8d5
    • affected: cef401de7be8c4e155c6746bfccf721a4fa5fab9 up to before 78bf6b6bb19541d19fbda6242e7cfe2c682763c0
    • affected: cef401de7be8c4e155c6746bfccf721a4fa5fab9 up to before 760e1addc27ba1a7beb4a0a7e8b3e9ec49e7a34e
    • affected: cef401de7be8c4e155c6746bfccf721a4fa5fab9 up to before 3bd9e113d50034db99d7ef69fd8e5242d15e414a
    • affected: cef401de7be8c4e155c6746bfccf721a4fa5fab9 up to before 3884358a9286b17f389a72b1426fc4547c23c111
    • affected: cef401de7be8c4e155c6746bfccf721a4fa5fab9 up to before f84eca5817390257cef78013d0112481c503b4a3

  • Linux

    • affected: 3.9
    • unaffected: before 3.9
    • unaffected: 5.10.257 up to 5.10.*
    • unaffected: 5.15.208 up to 5.15.*
    • unaffected: 6.1.174 up to 6.1.*
    • unaffected: 6.6.141 up to 6.6.*
    • unaffected: 6.12.91 up to 6.12.*
    • unaffected: 6.18.33 up to 6.18.*
    • unaffected: 7.0.10 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, 23:30 UTC. Sources and licenses