CVE-2026-64563 (GCVE-0-2026-64563)

Vulnerability from cvelistv5 – Published: 2026-08-04 06:23 – Updated: 2026-08-09 18:34
VLAI
Title
rhashtable: clear stale iter->p on table restart
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
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 , < c39643ad99fea749be50615550e8f0e6d6e60694 (git)
Affected: 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 , < 042fda5c088015f18838e5c692659a7be60aeb26 (git)
Affected: 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 , < 3ff7c1dbf722cf3fa538672452ba182318e0fcc3 (git)
Affected: 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 , < 4169d9fb92f313ff8e7e83d733c1ecdcc93eebd3 (git)
Affected: 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 , < 8173f7e2ce67e6ca1d4763f3da14e5b01ce77456 (git)
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Linux Linux Affected: 4.18
Unaffected: 0 , < 4.18 (semver)
Unaffected: 6.6.151 , ≤ 6.6.* (semver)
Unaffected: 6.12.103 , ≤ 6.12.* (semver)
Unaffected: 6.18.42 , ≤ 6.18.* (semver)
Unaffected: 7.1.6 , ≤ 7.1.* (semver)
Unaffected: 7.2-rc5 , ≤ * (original_commit_for_fix)
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{
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          "product": "Linux",
          "programFiles": [
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          "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"
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            "version": "3.1"
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              "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."
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64563",
    "datePublished": "2026-08-04T06:23:22.601Z",
    "dateReserved": "2026-07-19T15:36:31.797Z",
    "dateUpdated": "2026-08-09T18:34:59.800Z",
    "state": "PUBLISHED"
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    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-08-08T23:29:27Z",
      "cve": "CVE-2026-64563",
      "id": "CVE-2026-64563",
      "initial_release_date": "2026-08-06T23:56:43Z",
      "product_status:known_affected": "243",
      "product_status:known_not_affected": "53",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-64563",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-64563.json",
      "version": "3"
    }
  }
}



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Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
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Detection rules are retrieved from Rulezet.