138 lines
8.0 KiB
JSON
138 lines
8.0 KiB
JSON
{
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"dataType": "CVE_RECORD",
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"dataVersion": "5.2",
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"cveMetadata": {
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"cveId": "CVE-2026-64140",
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"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"state": "PUBLISHED",
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"assignerShortName": "Linux",
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"dateReserved": "2026-07-19T07:54:57.037Z",
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"datePublished": "2026-07-19T15:40:33.194Z",
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"dateUpdated": "2026-08-05T12:39:40.506Z"
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},
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"containers": {
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"cna": {
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"providerMetadata": {
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"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"shortName": "Linux",
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"dateUpdated": "2026-08-05T12:39:40.506Z"
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},
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"descriptions": [
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{
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"lang": "en",
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix null pointer dereference in proc_show_files()\n\nWhen a SMB2 client opens a file with a durable v2 handle and then issues\nSMB2 SESSION_LOGOFF, session_fd_check() clears fp->tcon = NULL on the\nreconnectable file pointer but leaves the fp registered in global_ft.idr\nuntil the durable scavenger fires (up to fp->durable_timeout seconds\nlater).\n\nDuring that window any read of /proc/fs/ksmbd/files (mode 0400) panics\nthe kernel because proc_show_files() walks global_ft.idr and\nunconditionally dereferences fp->tcon->id with no NULL guard.\n\nReproducer requires only a successful SMB2 SESSION_SETUP and a share\nconfigured with 'durable handles = yes'. KASAN report on mainline\n70390501d194:\n\n general protection fault, probably for non-canonical address\n 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI\n KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]\n RIP: 0010:proc_show_files+0x118/0x740\n Call Trace:\n proc_show_files+0x118/0x740\n seq_read_iter+0x4ef/0xe10\n proc_reg_read_iter+0x1b7/0x280\n ...\n\nGuard the dereference. A durable-disconnected fp legitimately has no\ntcon; report its tree id as 0 rather than oopsing."
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}
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],
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"metrics": [
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{
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"cvssV3_1": {
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"version": "3.1",
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"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
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"baseScore": 7.5,
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"baseSeverity": "HIGH"
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},
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"scenarios": [
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{
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"lang": "en",
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"value": "AV:N - The poisoned durable-handle state is created remotely over ksmbd's TCP/445 SMB2 path (SESSION_SETUP, TREE_CONNECT, CREATE with durable v2, SESSION_LOGOFF); ksmbd is a network-facing in-kernel SMB server per kernel CVSS guidance.\nAC:L - An attacker fully controls the SMB2 sequence that leaves `fp->tcon = NULL` while the file remains in `global_ft.idr`; once that state exists, any read of `/proc/fs/ksmbd/files` deterministically oopses, and the window lasts up to `fp->durable_timeout` seconds (repeatable).\nPR:N - Exploitation requires only network reachability to ksmbd plus a successful SMB2 SESSION_SETUP (guest or any configured share account); no host root or kernel capabilities are needed on the attacker side to plant the corrupt durable-handle entry.\nUI:N - No victim user action (opening files, mounting shares, clicking links) is required; the crash is triggered by kernel procfs iteration, not by end-user interaction.\nS:U - Impact is a kernel NULL pointer dereference/panic within the ksmbd/kernel security authority; it does not cross VM, IOMMU, or sandbox boundaries.\nC:N - This is a pure NULL pointer dereference at `fp->tcon->id` with no out-of-bounds read, UAF, or other memory corruption that could leak kernel data.\nI:N - The bug is a read of address 0 through a NULL `fp->tcon` pointer; it provides no write primitive, type confusion, or control-flow hijack opportunity.\nA:H - Unconditional dereference of NULL `fp->tcon` in `proc_show_files()` causes a kernel general protection fault/oops (KASAN null-ptr-deref), crashing or severely disrupting the host."
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}
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]
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}
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],
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"affected": [
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "unaffected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"fs/smb/server/vfs_cache.c"
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],
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"versions": [
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{
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"version": "b38f99c1217ae04753340f0fdcd8f35bf56841dc",
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"lessThan": "8eab081627b67216d1c8f638b68289b500dc9a6b",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "b38f99c1217ae04753340f0fdcd8f35bf56841dc",
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"lessThan": "904901561e61a2b559070b20c74a8c95491f30aa",
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"status": "affected",
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"versionType": "git"
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}
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]
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},
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "affected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"fs/smb/server/vfs_cache.c"
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],
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"versions": [
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{
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"version": "7.0",
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"status": "affected"
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},
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{
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"version": "0",
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"lessThan": "7.0",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.0.11",
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"lessThanOrEqual": "7.0.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.1",
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"lessThanOrEqual": "*",
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"status": "unaffected",
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"versionType": "original_commit_for_fix"
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}
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]
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}
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],
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"cpeApplicability": [
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{
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"nodes": [
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{
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"operator": "OR",
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"negate": false,
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"cpeMatch": [
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "7.0",
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"versionEndExcluding": "7.0.11"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "7.0",
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"versionEndExcluding": "7.1"
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}
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]
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}
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]
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}
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],
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"references": [
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{
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"url": "https://git.kernel.org/stable/c/8eab081627b67216d1c8f638b68289b500dc9a6b"
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},
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{
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"url": "https://git.kernel.org/stable/c/904901561e61a2b559070b20c74a8c95491f30aa"
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}
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],
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"title": "ksmbd: fix null pointer dereference in proc_show_files()",
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"x_generator": {
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"engine": "bippy-1.2.0"
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