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CVE-2026-63830

net: skmsg: preserve sg.copy across SG transforms

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.261, 5.15.212, 6.1.177, 6.6.144, 6.12.95, and 2 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: yes
  • Technical impact: total

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: yes · Technical impact: total

  3. Record last updated

Affected versions

  • Linux Linux

    From d3b18ad31f93d0b6bae105c679018a1ba7daa9ca · fixed in f126eed589eec6f201405abbc398844042ef6d57; From d3b18ad31f93d0b6bae105c679018a1ba7daa9ca · fixed in 31a110642b5fb5e61940cbcfb503445ac4f28017; From d3b18ad31f93d0b6bae105c679018a1ba7daa9ca · fixed in 9bb86d8184b37503816150c4a6ad3c17dfdbe827; From d3b18ad31f93d0b6bae105c679018a1ba7daa9ca · fixed in 0eb4c16c4adb262763bda870a8ed38a1a9dec7ec; From d3b18ad31f93d0b6bae105c679018a1ba7daa9ca · fixed in d22cc92bc41290e5783a72375e0843d9435f6001; From d3b18ad31f93d0b6bae105c679018a1ba7daa9ca · fixed in 1acdd14c0990dd1cd4b6534f00366d2e6dfce05f; From d3b18ad31f93d0b6bae105c679018a1ba7daa9ca · fixed in 21ed9540a8e1906dfcbc1bb82ba9b4de4fa4bd6d; From d3b18ad31f93d0b6bae105c679018a1ba7daa9ca · fixed in 406e8a651a7b854c41fecd5117bb282b3a6c2c6b

  • Linux Linux

    4.20

  • KernelLinux

    From 4.20.0 · fixed in 5.10.261; From 5.11.0 · fixed in 5.15.212; From 5.16.0 · fixed in 6.1.177; From 6.2.0 · fixed in 6.6.144; From 6.7.0 · fixed in 6.12.95; From 6.13.0 · fixed in 6.18.38; From 6.19.0 · fixed in 7.1.3

References 8

git.kernel.org