163 lines
10 KiB
JSON
163 lines
10 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-2026-64044",
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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": "2026-07-19T07:54:57.029Z",
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"datePublished": "2026-07-19T15:39:29.869Z",
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"dateUpdated": "2026-08-05T12:38:36.035Z"
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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": "2026-08-05T12:38:36.035Z"
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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\novpn: respect peer refcount in CMD_NEW_PEER error path\n\novpn_nl_peer_new_doit()'s error path calls ovpn_peer_release() directly\nrather than ovpn_peer_put(), bypassing the kref. The accompanying\ncomment (\"peer was not yet hashed, thus it is not used in any context\")\nholds for UDP but not for TCP.\n\nFor UDP, the ovpn_socket union uses the .ovpn arm and never points back\nat a peer; UDP encap_recv looks up peers via the not-yet-populated\nhashtables, so the new peer is unreachable until ovpn_peer_add()\npublishes it.\n\nFor TCP, ovpn_socket_new() sets ovpn_sock->peer and\novpn_tcp_socket_attach() publishes ovpn_sock via rcu_assign_sk_user_data().\nFrom that moment until ovpn_socket_release() detaches in the error path,\nthe TCP fd is fully wired: userspace recvmsg / sendmsg / close / poll\non the fd, as well as the strparser-driven ovpn_tcp_rcv() path, can\nreach the peer through sk_user_data -> ovpn_sock->peer and bump its\nrefcount via ovpn_peer_hold().\n\novpn_tcp_socket_wait_finish() (called inside ovpn_socket_release())\ndrains strparser and the tx work, but does not synchronize with\nuserspace syscall callers that already hold a peer reference. If\novpn_nl_peer_modify() or ovpn_peer_add() returns an error while such\na caller is in flight - notably an ovpn_tcp_recvmsg() blocked in\n__skb_recv_datagram() on peer->tcp.user_queue - the direct\novpn_peer_release() destroys the peer while the caller still holds\nthe reference, and the eventual ovpn_peer_put() from that caller\noperates on freed memory.\n\nReplace the direct destructor call with ovpn_peer_put() so the kref\ncorrectly defers destruction until the last reference is dropped.\nIn the common case where no concurrent user is present, behaviour is\nunchanged: the kref hits zero immediately and ovpn_peer_release_kref()\nruns the same destructor.\n\nWith this conversion ovpn_peer_release() has no callers outside peer.c\n- ovpn_peer_release_kref() in the same translation unit is the only\nremaining user - so make it static and drop its declaration from\npeer.h."
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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:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
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"baseScore": 7.8,
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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:L - The bug is triggered from the OVPN_CMD_PEER_NEW genetlink handler reached only via local netlink syscalls; remote TCP data can participate in the race but cannot alone reach the premature ovpn_peer_release() error path.\nAC:L - Exploitation requires a race between a failing CMD_NEW_PEER netlink message and a concurrent local holder of a peer reference, and the attacker controls both sides by blocking recvmsg on the TCP fd while issuing the failing netlink command.\nPR:L - All OVPN genetlink operations require GENL_ADMIN_PERM (CAP_NET_ADMIN), and creating the ovpn interface requires the same capability, which an unprivileged user can obtain inside a user namespace.\nUI:N - No victim interaction is required; the attacker configures the ovpn interface, TCP socket, and concurrent threads themselves to trigger the error-path UAF.\nS:U - The UAF corrupts kernel heap memory and enables standard kernel privilege escalation within the same security authority, not a cross-boundary escape such as guest-to-host or IOMMU bypass.\nC:H - Use-after-free of struct ovpn_peer allows an attacker to read freed slab memory and obtain arbitrary kernel memory disclosure primitives.\nI:H - Use-after-free of struct ovpn_peer enables heap grooming and control of freed object contents, providing a path to arbitrary kernel memory writes and code execution.\nA:H - The UAF causes ovpn_peer_put() to operate on freed memory, which can trigger kernel oops, panic, or crash during reference decrements on corrupted kref state."
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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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"drivers/net/ovpn/netlink.c",
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"drivers/net/ovpn/peer.c",
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"drivers/net/ovpn/peer.h"
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],
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"versions": [
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{
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"version": "11851cbd60ea1e5abbd97619d69845ead99303d6",
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"lessThan": "8298834912d76dbc82c12b6b4ab7590ed2bb8ae5",
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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": "11851cbd60ea1e5abbd97619d69845ead99303d6",
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"lessThan": "0c3ef71879c0264de6c42463031d9e057da87840",
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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": "11851cbd60ea1e5abbd97619d69845ead99303d6",
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"lessThan": "1fef6614673ff0846d30acdeeaf3cf98bb5f6116",
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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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"drivers/net/ovpn/netlink.c",
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"drivers/net/ovpn/peer.c",
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"drivers/net/ovpn/peer.h"
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],
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"versions": [
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{
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"version": "6.16",
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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": "6.16",
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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": "6.18.34",
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"lessThanOrEqual": "6.18.*",
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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": "6.16",
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"versionEndExcluding": "6.18.34"
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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": "6.16",
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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": "6.16",
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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/8298834912d76dbc82c12b6b4ab7590ed2bb8ae5"
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},
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{
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"url": "https://git.kernel.org/stable/c/0c3ef71879c0264de6c42463031d9e057da87840"
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},
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{
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"url": "https://git.kernel.org/stable/c/1fef6614673ff0846d30acdeeaf3cf98bb5f6116"
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}
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],
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"title": "ovpn: respect peer refcount in CMD_NEW_PEER error path",
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"x_generator": {
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"engine": "bippy-1.2.0"
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}
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}
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}
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} |