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CVE-2026-43284

xfrm: esp: avoid in-place decrypt on shared skb frags

CVSS 3.1 High 8.8

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: xfrm: esp: avoid in-place decrypt on shared skb frags MSG_SPLICE_PAGES can attach pages from a pipe directly to an skb. TCP marks such skbs with SKBFL_SHARED_FRAG after skb_splice_from_iter(), so later paths that may modify packet data can first make a private copy. The IPv4/IPv6 datagram append paths did not set this flag when splicing pages into UDP skbs. That leaves an ESP-in-UDP packet made from shared pipe pages looking like an ordinary uncloned nonlinear skb. ESP input then takes the no-COW fast path for uncloned skbs without a frag_list and decrypts in place over data that is not owned privately by the skb. Mark IPv4/IPv6 datagram splice frags with SKBFL_SHARED_FRAG, matching TCP. Also make ESP input fall back to skb_cow_data() when the flag is present, so ESP does not decrypt externally backed frags in place. Private nonlinear skb frags still use the existing fast path. This intentionally does not change ESP output. In esp_output_head(), the path that appends the ESP trailer to existing skb tailroom without calling skb_cow_data() is not reachable for nonlinear skbs: skb_tailroom() returns zero when skb->data_len is nonzero, while ESP tailen is positive. Thus ESP output will either use the separate destination-frag path or fall back to skb_cow_data().

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 3.1 High 7.8

Score published by CISA-ADP in the CVE record.

CVSS:3.1/AV:L/AC:H/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: High

    The attack depends on conditions outside the attacker's control, so it takes preparation.

  • 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 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
0.94194 (94.2% probability)
Percentile
99.8%
Scores of
Nov 10, 2026
Model
v2026.06.15

CISA assessment as of May 8, 2026

Stakeholder-Specific Vulnerability Categorization (SSVC) decision points added by CISA.
Exploitation
Public proof of concept recorded by CISA
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: cac2661c53f35cbe651bef9b07026a5a05ab8ce0 up to before a6cb440f274a22456ef3e86b457344f1678f38f9
    • affected: cac2661c53f35cbe651bef9b07026a5a05ab8ce0 up to before ab8b995323e5237041472d07e5055f5f7dcdf15b
    • affected: cac2661c53f35cbe651bef9b07026a5a05ab8ce0 up to before fe785bb3a8096dffcc4048a85cd0c83337eeecad
    • affected: cac2661c53f35cbe651bef9b07026a5a05ab8ce0 up to before 5d55c7336f8032d434adcc5fab987ccc93a44aec
    • affected: cac2661c53f35cbe651bef9b07026a5a05ab8ce0 up to before 8253aab4659ca16116b522203c2a6b18dccacea7
    • affected: cac2661c53f35cbe651bef9b07026a5a05ab8ce0 up to before 50ed1e7873100f77abad20fd31c51029bc49cd03
    • affected: cac2661c53f35cbe651bef9b07026a5a05ab8ce0 up to before b54edf1e9a3fd3491bdcb82a21f8d21315271e0d
    • affected: cac2661c53f35cbe651bef9b07026a5a05ab8ce0 up to before 71a1d9d985d26716f74d21f18ee8cac821b06e97
    • affected: cac2661c53f35cbe651bef9b07026a5a05ab8ce0 up to before 52646cbd00e765a6db9c3afe9535f26218276034
    • affected: cac2661c53f35cbe651bef9b07026a5a05ab8ce0 up to before f4c50a4034e62ab75f1d5cdd191dd5f9c77fdff4

  • Linux

    • affected: 4.11
    • unaffected: before 4.11
    • unaffected: 5.10.255 up to 5.10.*
    • unaffected: 5.15.205 up to 5.15.*
    • unaffected: 5.15.206 up to 5.15.*
    • unaffected: 6.1.171 up to 6.1.*
    • unaffected: 6.1.172 up to 6.1.*
    • unaffected: 6.6.138 up to 6.6.*
    • unaffected: 6.12.87 up to 6.12.*
    • unaffected: 6.18.28 up to 6.18.*
    • unaffected: 7.0.5 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. 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, 19:52 UTC. Sources and licenses