net: skmsg: preserve sg.copy across SG transforms

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-63830
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-19 12:16:56 UTC
Updated2026-07-20 15:16:49 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: net: skmsg: preserve sg.copy across SG transforms The sk_msg sg.copy bitmap is part of the scatterlist entry ownership state. A set bit tells sk_msg_compute_data_pointers() not to expose the entry through writable BPF ctx->data. This protects entries backed by pages that are not private to the sk_msg, such as splice-backed file page-cache pages. Several sk_msg transform paths move, copy, split, or compact msg->sg.data[] entries without moving the matching sg.copy bit. This can make an externally backed entry arrive at a new slot with a clear copy bit. A later SK_MSG verdict can then expose sg_virt(sge) as writable ctx->data and BPF stores can modify the original page cache. Keep sg.copy synchronized with sg.data[] whenever entries are transferred, shifted, split, or copied into a new sk_msg. Clear the bit when an entry is replaced by a newly allocated private page or freed. This covers the BPF pull/push/pop helpers, sk_msg_shift_left/right(), sk_msg_xfer(), and tls_split_open_record(), including the partial tail entry created during TLS open-record splitting.

Risk And Classification

Primary CVSS: v3.1 9.4 CRITICAL from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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

EPSS: 0.001610000 probability, percentile 0.057120000 (date 2026-07-20)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary9.4CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
3.1CNADECLARED9.4CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
Low

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected d3b18ad31f93d0b6bae105c679018a1ba7daa9ca 9bb86d8184b37503816150c4a6ad3c17dfdbe827 git Not specified
CNA Linux Linux affected d3b18ad31f93d0b6bae105c679018a1ba7daa9ca 0eb4c16c4adb262763bda870a8ed38a1a9dec7ec git Not specified
CNA Linux Linux affected d3b18ad31f93d0b6bae105c679018a1ba7daa9ca d22cc92bc41290e5783a72375e0843d9435f6001 git Not specified
CNA Linux Linux affected d3b18ad31f93d0b6bae105c679018a1ba7daa9ca 1acdd14c0990dd1cd4b6534f00366d2e6dfce05f git Not specified
CNA Linux Linux affected d3b18ad31f93d0b6bae105c679018a1ba7daa9ca 21ed9540a8e1906dfcbc1bb82ba9b4de4fa4bd6d git Not specified
CNA Linux Linux affected d3b18ad31f93d0b6bae105c679018a1ba7daa9ca 406e8a651a7b854c41fecd5117bb282b3a6c2c6b git Not specified
CNA Linux Linux affected 4.20 Not specified
CNA Linux Linux unaffected 4.20 semver Not specified
CNA Linux Linux unaffected 6.1.177 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.144 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.95 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.38 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.3 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/406e8a651a7b854c41fecd5117bb282b3a6c2c6b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/21ed9540a8e1906dfcbc1bb82ba9b4de4fa4bd6d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/d22cc92bc41290e5783a72375e0843d9435f6001 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/0eb4c16c4adb262763bda870a8ed38a1a9dec7ec 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/1acdd14c0990dd1cd4b6534f00366d2e6dfce05f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/9bb86d8184b37503816150c4a6ad3c17dfdbe827 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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