CyberSecBulletin
CVE-2026-64563NVD status: Analyzed

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-64563 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions ba510b5e9fe396497d31162acb579f210adfe6c8, a0406c40c6638c5ae50257db6297b2fba6c9ba16, 0955b65c2b47c30b439e2cf1b1e375073aa0413a as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.17% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to ba510b5e9fe396497d31162acb579f210adfe6c8 or a0406c40c6638c5ae50257db6297b2fba6c9ba16 or 0955b65c2b47c30b439e2cf1b1e375073aa0413a or c39643ad99fea749be50615550e8f0e6d6e60694, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.265 or 5.15.216 or 6.1.183 or 6.6.151, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 up to, but not including, ba510b5e9fe396497d31162acb579f210adfe6c8; 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 up to, but not including, a0406c40c6638c5ae50257db6297b2fba6c9ba16; 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 up to, but not including, 0955b65c2b47c30b439e2cf1b1e375073aa0413a; 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 up to, but not including, c39643ad99fea749be50615550e8f0e6d6e60694; 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 up to, but not including, 042fda5c088015f18838e5c692659a7be60aeb26; 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 up to, but not including, 3ff7c1dbf722cf3fa538672452ba182318e0fcc3; 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 up to, but not including, 4169d9fb92f313ff8e7e83d733c1ecdcc93eebd3; 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 up to, but not including, 8173f7e2ce67e6ca1d4763f3da14e5b01ce77456; and 1 more rangesba510b5e9fe396497d31162acb579f210adfe6c8, a0406c40c6638c5ae50257db6297b2fba6c9ba16, 0955b65c2b47c30b439e2cf1b1e375073aa0413a, c39643ad99fea749be50615550e8f0e6d6e60694, 042fda5c088015f18838e5c692659a7be60aeb26, 3ff7c1dbf722cf3fa538672452ba182318e0fcc3
LinuxLinux Kernel4.18 up to, but not including, 5.10.265; 5.11 up to, but not including, 5.15.216; 5.16 up to, but not including, 6.1.183; 6.2 up to, but not including, 6.6.151; 6.7 up to, but not including, 6.12.103; 6.13 up to, but not including, 6.18.42; 6.19 up to, but not including, 7.1.6; 7.25.10.265, 5.15.216, 6.1.183, 6.6.151, 6.12.103, 6.18.42

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.

Official 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

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

How developers prevent this class of flaw

  • Choose a language that provides automatic memory management.
  • When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.

More Use After Free vulnerabilities (CWE-416)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Use After Free vulnerabilities

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