In 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.
References
Configurations
No configuration.
History
No history.
Information
Published : 2026-07-19 12:16
Updated : 2026-08-17 05:17
NVD link : CVE-2026-63830
Mitre link : CVE-2026-63830
CVE.ORG link : CVE-2026-63830
JSON object : View
Products Affected
No product.
CWE
No CWE.