156 lines
9.3 KiB
JSON
156 lines
9.3 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-2026-99277",
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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": "2026-09-25T10:25:14.405Z",
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"datePublished": "2026-11-07T14:08:46.710Z",
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"dateUpdated": "2026-11-10T16:57:40.367Z"
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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": "2026-11-10T16:57:40.367Z"
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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: hold a connection reference for each session channel\n\nksmbd_session_unregister() removes a session from the global and per-\nconnection tables before dropping the table reference. A concurrent\nreference holder can keep the session and its channel list alive after\nthose removals.\n\nConnection cleanup can no longer find the unpublished session to remove its\nchannels. Since a channel only stores a raw conn pointer, the connection\ncan be freed while another session reference holder is still accessing it,\nfor example during SMB3.1.1 binding or a procfs read.\n\nTake a connection reference when registering a channel and release it on\ninsertion failure, channel removal, or final session destruction. Keep the\nchannels and signing keys until the session is destroyed so a response can\nstill be signed after the session has been unregistered."
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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:H/PR:L/UI:N/S:U/C:H/I:H/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 - register_session_channel() runs from smb2_sess_setup() after ksmbd_conn_handler_loop() queues an SMB2 SESSION_SETUP read from the TCP socket. That command stores the connection in chann->conn without a reference; a later failing SESSION_SETUP calls ksmbd_session_unregister(), and ksmbd_conn_free() can free it while the channel still points at it.\nAC:H - ksmbd_session_unregister() drops an established session only after session_setup_reauth sets SMB2_SESSION_IN_PROGRESS because sess->kerberos_expiry has passed. The attacker's chann->conn->cipher_type read is smb2_sess_setup()'s SMB 3.1.1 binding arm, entered only when KSMBD_GLOBAL_FLAG_SMB3_MULTICHANNEL is already set, immediately after ksmbd_session_lookup_slowpath(), with no delay the attacker can hold across __ksmbd_conn_release_work().\nPR:L - register_session_channel() writes chann->conn only after ntlm_authenticate() or krb5_authenticate() succeeds, and the reauth path that unregisters a session which already has channels depends on kerberos_expiry set by ksmbd_krb5_authenticate(). A SESSION_SETUP rejected before authentication stores no channel.\nUI:N - The client sends the SESSION_SETUP that registers the channel, the failing reauth SESSION_SETUP that calls ksmbd_session_unregister(), and the TCP close that reaches ksmbd_server_terminate_conn() and ksmbd_conn_free().\nS:U - The freed object is a ksmbd_conn in the host kernel that serves this SMB session, so the corruption stays in that kernel security authority.\nC:H - __ksmbd_conn_release_work() kfree_sensitive()s the conn while the channel keeps the pointer. smb2_sess_setup() then reads chann->conn->cipher_type, and show_proc_session() follows chan->conn->vals and inet_addr; reclaiming the slab lets those uses disclose the replacement object.\nI:H - show_proc_session() down_read()s chan->conn->session_lock through the channel's raw pointer after the connection can already have been freed, writing the rwsem of whatever reused that slot. The use-after-free of ksmbd_conn is a heap write against that allocation.\nA:H - smb2_sess_setup()'s read of chann->conn->cipher_type and show_proc_session()'s lock of chan->conn->session_lock both use the ksmbd_conn after __ksmbd_conn_release_work() freed it, which oopses the kernel."
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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/mgmt/user_session.c",
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"fs/smb/server/smb2pdu.c"
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],
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"versions": [
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{
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"version": "d7fd1f98607f2cd358e583f9548bdf0173090a86",
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"lessThan": "4b333aed69cfc2c8687b86b6a4364a0dffc16dd8",
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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": "d7fd1f98607f2cd358e583f9548bdf0173090a86",
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"lessThan": "add8d7fb04efe564193df73581889c62fc0016f1",
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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": "c99ea7855124ca1428a1e59c2b4590aaef34eacf",
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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": "7.2.8",
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"lessThan": "7.3",
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"status": "affected",
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"versionType": "semver"
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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/mgmt/user_session.c",
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"fs/smb/server/smb2pdu.c"
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],
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"versions": [
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{
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"version": "7.3",
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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": "7.3",
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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": "7.3.2",
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"lessThanOrEqual": "7.3.*",
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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": "7.4-rc1",
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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": "7.3",
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"versionEndExcluding": "7.3.2"
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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": "7.3",
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"versionEndExcluding": "7.4-rc1"
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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": "7.2.8"
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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/4b333aed69cfc2c8687b86b6a4364a0dffc16dd8"
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},
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{
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"url": "https://git.kernel.org/stable/c/add8d7fb04efe564193df73581889c62fc0016f1"
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}
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],
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"title": "ksmbd: hold a connection reference for each session channel",
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"x_generator": {
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}
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} |