# CVE-2026-64563: CVE-2026-64563

Status: published. Published: 2026-08-04. Updated: 2026-11-03.

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

## Remediation

No remediation reported in collected sources

## Affected products and versions

Not reported in collected sources.

## Severity and prioritization

- CVSS 3.1: 7.8 (high); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H; source: NVD: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: exploitation none; automatable no; technical impact total; source NVD SSVC: 134c704f-9b21-4f2e-91b3-4a467353bcc0

- Weaknesses: CWE-416

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/042fda5c088015f18838e5c692659a7be60aeb26 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/0955b65c2b47c30b439e2cf1b1e375073aa0413a (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/3ff7c1dbf722cf3fa538672452ba182318e0fcc3 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/4169d9fb92f313ff8e7e83d733c1ecdcc93eebd3 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/8173f7e2ce67e6ca1d4763f3da14e5b01ce77456 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/a0406c40c6638c5ae50257db6297b2fba6c9ba16 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/ba510b5e9fe396497d31162acb579f210adfe6c8 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/c39643ad99fea749be50615550e8f0e6d6e60694 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

## Provenance

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64563; retrieved 2026-11-03; source updated 2026-11-03

Revision: 6433e88ab645a7c8c86c76f47b601b7e219d5edfcbf9e4554f842d7bc415ac48

Canonical: https://y2.dev/cve/CVE-2026-64563

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