{"id":"CVE-2025-40004","state":"PUBLISHED","title":"net/9p: Fix buffer overflow in USB transport layer","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.","publishedAt":"2025-10-20T05:26:08.787Z","updatedAt":"2026-05-11T21:40:36.949Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a3be076dc174d9022a71a12554feb4c97b5c4d5c","status":"affected","lessThan":"0da18d49f874d444ad83c8a546fa33bfcf2f582c","versionType":"git"},{"version":"a3be076dc174d9022a71a12554feb4c97b5c4d5c","status":"affected","lessThan":"df8462f0fc045b4475dc494a5787a03c972ba2a2","versionType":"git"},{"version":"a3be076dc174d9022a71a12554feb4c97b5c4d5c","status":"affected","lessThan":"c04db81cd0288dfc68b7a0f7d09bd49b40bba451","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/9p/trans_usbg.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.12","versionType":"semver"},{"version":"6.12.53","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.17.3","status":"unaffected","lessThanOrEqual":"6.17.*","versionType":"semver"},{"version":"6.18","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/9p/trans_usbg.c"]}],"references":["https://git.kernel.org/stable/c/0da18d49f874d444ad83c8a546fa33bfcf2f582c","https://git.kernel.org/stable/c/df8462f0fc045b4475dc494a5787a03c972ba2a2","https://git.kernel.org/stable/c/c04db81cd0288dfc68b7a0f7d09bd49b40bba451"],"weaknesses":[],"ingestedAt":"2026-10-29T20:09:09.358Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/40xxx/CVE-2025-40004.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-40004","state":"PUBLISHED","datePublished":"2025-10-20T05:26:08.787Z","dateUpdated":"2026-05-11T21:40:36.949Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-04-16T07:20:57.151Z"},"containers":{"cna":{"title":"net/9p: Fix buffer overflow in USB transport layer","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a3be076dc174d9022a71a12554feb4c97b5c4d5c","status":"affected","lessThan":"0da18d49f874d444ad83c8a546fa33bfcf2f582c","versionType":"git"},{"version":"a3be076dc174d9022a71a12554feb4c97b5c4d5c","status":"affected","lessThan":"df8462f0fc045b4475dc494a5787a03c972ba2a2","versionType":"git"},{"version":"a3be076dc174d9022a71a12554feb4c97b5c4d5c","status":"affected","lessThan":"c04db81cd0288dfc68b7a0f7d09bd49b40bba451","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/9p/trans_usbg.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.12","versionType":"semver"},{"version":"6.12.53","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.17.3","status":"unaffected","lessThanOrEqual":"6.17.*","versionType":"semver"},{"version":"6.18","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/9p/trans_usbg.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/0da18d49f874d444ad83c8a546fa33bfcf2f582c"},{"url":"https://git.kernel.org/stable/c/df8462f0fc045b4475dc494a5787a03c972ba2a2"},{"url":"https://git.kernel.org/stable/c/c04db81cd0288dfc68b7a0f7d09bd49b40bba451"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T21:40:36.949Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.12.53"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.17.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.18"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}