CVE-2026-64563 (GCVE-0-2026-64563)
Vulnerability from cvelistv5
Published
2026-08-04 06:23
Modified
2026-08-19 16:28
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
rhashtable: clear stale iter->p on table restart
rhashtable_walk_start_check() has two restart paths when resuming a walk.
When iter->walker.tbl is valid, it re-validates iter->p against the table
and sets iter->p = NULL if the object is gone. When iter->walker.tbl is
NULL (table was freed during resize), it resets slot and skip but forgets
to clear iter->p.
rhashtable_walk_next() then dereferences the stale iter->p, reading
freed memory. This is a use-after-free.
Any caller that does multi-fragment rhashtable walks across
walk_stop/walk_start boundaries is affected. Concrete cases include
netlink_diag (__netlink_diag_dump in net/netlink/diag.c) and TIPC
(tipc_nl_sk_walk in net/tipc/socket.c).
Crash stack (netlink_diag):
BUG: KASAN: slab-use-after-free in rhashtable_walk_next+0x365/0x3c0
Read of size 8 at addr ffff88801a9d2438 (freed kmalloc-2k, offset 1080)
Call Trace:
rhashtable_walk_next+0x365/0x3c0 (lib/rhashtable.c:1016)
__netlink_diag_dump+0x160/0x760 (net/netlink/diag.c:122)
netlink_diag_dump+0xc2/0x240
netlink_dump+0x5bc/0x1270
netlink_recvmsg+0x7a3/0x980
sock_recvmsg+0x1bc/0x200
__sys_recvfrom+0x1d4/0x2c0
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 Version: 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 Version: 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 Version: 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 Version: 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 Version: 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 Version: 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 Version: 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 |
||
{
"containers": {
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"programFiles": [
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{
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"status": "unaffected",
"version": "5.15.216",
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{
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"status": "unaffected",
"version": "6.1.183",
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{
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"version": "6.6.151",
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{
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"version": "6.12.103",
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{
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"version": "7.1.6",
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{
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"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
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}
],
"negate": false,
"operator": "OR"
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],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrhashtable: clear stale iter-\u003ep on table restart\n\nrhashtable_walk_start_check() has two restart paths when resuming a walk.\nWhen iter-\u003ewalker.tbl is valid, it re-validates iter-\u003ep against the table\nand sets iter-\u003ep = NULL if the object is gone. When iter-\u003ewalker.tbl is\nNULL (table was freed during resize), it resets slot and skip but forgets\nto clear iter-\u003ep.\n\nrhashtable_walk_next() then dereferences the stale iter-\u003ep, reading\nfreed memory. This is a use-after-free.\n\nAny caller that does multi-fragment rhashtable walks across\nwalk_stop/walk_start boundaries is affected. Concrete cases include\nnetlink_diag (__netlink_diag_dump in net/netlink/diag.c) and TIPC\n(tipc_nl_sk_walk in net/tipc/socket.c).\n\nCrash stack (netlink_diag):\n BUG: KASAN: slab-use-after-free in rhashtable_walk_next+0x365/0x3c0\n Read of size 8 at addr ffff88801a9d2438 (freed kmalloc-2k, offset 1080)\n Call Trace:\n rhashtable_walk_next+0x365/0x3c0 (lib/rhashtable.c:1016)\n __netlink_diag_dump+0x160/0x760 (net/netlink/diag.c:122)\n netlink_diag_dump+0xc2/0x240\n netlink_dump+0x5bc/0x1270\n netlink_recvmsg+0x7a3/0x980\n sock_recvmsg+0x1bc/0x200\n __sys_recvfrom+0x1d4/0x2c0"
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - Triggered via local netlink sock_diag dumps (e.g. netlink_diag over NETLINK_SOCK_DIAG) and similar local dump walkers such as TIPC_NL_SOCK_GET; not reachable from remote packet processing.\nAC:L - Attacker controls both sides of the race by running a multi-fragment rhashtable dump while concurrently creating/destroying netlink (or TIPC) sockets to force table resize and free the walked object.\nPR:L - An unprivileged local user can open NETLINK_SOCK_DIAG and dump without CAP_NET_ADMIN; CAP_NET_ADMIN is only required for SOCK_DESTROY, and TIPC_NL_SOCK_GET likewise has no admin permission flag.\nUI:N - Exploitation requires only attacker-issued syscalls (netlink dump plus concurrent socket churn); no victim action is needed.\nS:U - Impact is memory corruption within the host kernel authority (local privilege escalation/crash), not a cross-boundary escape such as guest-to-host or IOMMU bypass.\nC:H - Use-after-free read of a freed hashed object (e.g. netlink_sock) can be reclaimed via heap spray, yielding an arbitrary read primitive through subsequent walk/diag use of the corrupted pointer.\nI:H - UAF on a reclaimable slab object enables heap spraying and fake-object injection into the walk path, which can be leveraged for arbitrary write or control-flow hijacking.\nA:H - The demonstrated KASAN slab-use-after-free in rhashtable_walk_next can oops/panic the kernel, and UAFs remain crashable even when not fully exploited."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-19T16:28:34.797Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/ba510b5e9fe396497d31162acb579f210adfe6c8"
},
{
"url": "https://git.kernel.org/stable/c/a0406c40c6638c5ae50257db6297b2fba6c9ba16"
},
{
"url": "https://git.kernel.org/stable/c/0955b65c2b47c30b439e2cf1b1e375073aa0413a"
},
{
"url": "https://git.kernel.org/stable/c/c39643ad99fea749be50615550e8f0e6d6e60694"
},
{
"url": "https://git.kernel.org/stable/c/042fda5c088015f18838e5c692659a7be60aeb26"
},
{
"url": "https://git.kernel.org/stable/c/3ff7c1dbf722cf3fa538672452ba182318e0fcc3"
},
{
"url": "https://git.kernel.org/stable/c/4169d9fb92f313ff8e7e83d733c1ecdcc93eebd3"
},
{
"url": "https://git.kernel.org/stable/c/8173f7e2ce67e6ca1d4763f3da14e5b01ce77456"
}
],
"title": "rhashtable: clear stale iter-\u003ep on table restart",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-64563",
"datePublished": "2026-08-04T06:23:22.601Z",
"dateReserved": "2026-07-19T15:36:31.797Z",
"dateUpdated": "2026-08-19T16:28:34.797Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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