CVE-2026-64563: Linux kernel · rhashtable: clear stale iter->p on table restart
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.8 High · fixed in c39643ad99fea749be50615550e8f0e6d6e60694 : patch Linux kernel soon.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in c39643ad99fea749be50615550e8f0e6d6e60694, ba510b5e9fe396497d31162acb579f210adfe6c8, a0406c40c6638c5ae50257db6297b2fba6c9ba16 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 4 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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Description
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
- git.kernel.org/stable/c/ba510b5e9fe396497d31162acb579f210adfe6c8 (opens in a new tab)
- git.kernel.org/stable/c/a0406c40c6638c5ae50257db6297b2fba6c9ba16 (opens in a new tab)
- git.kernel.org/stable/c/0955b65c2b47c30b439e2cf1b1e375073aa0413a (opens in a new tab)
- git.kernel.org/stable/c/c39643ad99fea749be50615550e8f0e6d6e60694 (opens in a new tab)
- git.kernel.org/stable/c/042fda5c088015f18838e5c692659a7be60aeb26 (opens in a new tab)
- git.kernel.org/stable/c/3ff7c1dbf722cf3fa538672452ba182318e0fcc3 (opens in a new tab)
- git.kernel.org/stable/c/4169d9fb92f313ff8e7e83d733c1ecdcc93eebd3 (opens in a new tab)
- git.kernel.org/stable/c/8173f7e2ce67e6ca1d4763f3da14e5b01ce77456 (opens in a new tab)