{"cve":"CVE-2025-40004","nvd":{"published":"2025-10-20T06:15:36.280","modified":"2026-10-19T21:10:00.160","status":"Deferred","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/9p: Fix buffer overflow in USB transport layer\n\nA buffer overflow vulnerability exists in the USB 9pfs transport layer\nwhere inconsistent size validation between packet header parsing and\nactual data copying allows a malicious USB host to overflow heap buffers.\n\nThe issue occurs because:\n- usb9pfs_rx_header() validates only the declared size in packet header\n- usb9pfs_rx_complete() uses req->actual (actual received bytes) for\nmemcpy\n\nThis allows an attacker to craft packets with small declared size\n(bypassing validation) but large actual payload (triggering overflow\nin memcpy).\n\nAdd validation in usb9pfs_rx_complete() to ensure req->actual does not\nexceed the buffer capacity before copying data.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/0da18d49f874d444ad83c8a546fa33bfcf2f582c","https://git.kernel.org/stable/c/c04db81cd0288dfc68b7a0f7d09bd49b40bba451","https://git.kernel.org/stable/c/df8462f0fc045b4475dc494a5787a03c972ba2a2"],"products":[],"source":"nvd","synced_at":"2026-10-21T03:43:09.190223697+00:00"},"epss":{"cve":"CVE-2025-40004","score":0.00267,"percentile":0.1867,"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."]}