{"cve":"CVE-2026-63830","nvd":{"published":"2026-07-19T12:16:56.337","modified":"2026-10-22T18:14:48.593","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: skmsg: preserve sg.copy across SG transforms\n\nThe sk_msg sg.copy bitmap is part of the scatterlist entry ownership\nstate. A set bit tells sk_msg_compute_data_pointers() not to expose the\nentry through writable BPF ctx->data. This protects entries backed by\npages that are not private to the sk_msg, such as splice-backed file\npage-cache pages.\n\nSeveral sk_msg transform paths move, copy, split, or compact\nmsg->sg.data[] entries without moving the matching sg.copy bit. This can\nmake an externally backed entry arrive at a new slot with a clear copy\nbit. A later SK_MSG verdict can then expose sg_virt(sge) as writable\nctx->data and BPF stores can modify the original page cache.\n\nKeep sg.copy synchronized with sg.data[] whenever entries are\ntransferred, shifted, split, or copied into a new sk_msg. Clear the bit\nwhen an entry is replaced by a newly allocated private page or freed.\nThis covers the BPF pull/push/pop helpers, sk_msg_shift_left/right(),\nsk_msg_xfer(), and tls_split_open_record(), including the partial tail\nentry created during TLS open-record splitting.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L","score":9.4},"cwes":["CWE-863","CWE-269"],"references":["https://git.kernel.org/stable/c/0eb4c16c4adb262763bda870a8ed38a1a9dec7ec","https://git.kernel.org/stable/c/1acdd14c0990dd1cd4b6534f00366d2e6dfce05f","https://git.kernel.org/stable/c/21ed9540a8e1906dfcbc1bb82ba9b4de4fa4bd6d","https://git.kernel.org/stable/c/31a110642b5fb5e61940cbcfb503445ac4f28017","https://git.kernel.org/stable/c/406e8a651a7b854c41fecd5117bb282b3a6c2c6b"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-23T16:39:26.291718493+00:00"},"epss":{"cve":"CVE-2026-63830","score":0.00441,"percentile":0.38089,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}