Linux Kernel: ipset Dump Race Causes Use-After-Free (CVE-2026-64189)
CVE-2026-64189 Published on July 20, 2026
netfilter: ipset: fix race between dump and ip_set_list resize
In the Linux kernel, the following vulnerability has been resolved:
netfilter: ipset: fix race between dump and ip_set_list resize
The release path of ip_set_dump_do() and ip_set_dump_done() read
inst->ip_set_list via ip_set_ref_netlink(), a plain rcu_dereference_raw()
of the array pointer. These run from netlink_recvmsg() without the nfnl
mutex and without an RCU read-side critical section.
A concurrent ip_set_create() can grow the array: it publishes the new
array, calls synchronize_net() and then kvfree()s the old one. Since the
dump paths read the array outside any RCU reader, synchronize_net() does
not wait for them and the old array can be freed while they still index
into it, causing a use-after-free.
The dumped set itself stays pinned via set->ref_netlink, so only the
array load needs protecting. Take rcu_read_lock() around it, matching
ip_set_get_byname() and __ip_set_put_byindex().
BUG: KASAN: slab-use-after-free in ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1697)
Read of size 8 at addr ffff88800b5c4018 by task exploit/150
Call Trace:
...
kasan_report (mm/kasan/report.c:595)
ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1697)
netlink_dump (net/netlink/af_netlink.c:2325)
netlink_recvmsg (net/netlink/af_netlink.c:1976)
sock_recvmsg (net/socket.c:1159)
__sys_recvfrom (net/socket.c:2315)
...
Oops: general protection fault, probably for non-canonical address ... KASAN NOPTI
KASAN: maybe wild-memory-access in range [0x02d6...d0-0x02d6...d7]
RIP: 0010:ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1698)
Kernel panic - not syncing: Fatal exception
Products Associated with CVE-2026-64189
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Affected Versions
Linux:- Version 8a02bdd50b2ecb6d62121d2958d3ea186cc88ce7 and below ff86ea9b7fdf70564e60436fbee68c96bc459943 is affected.
- Version 8a02bdd50b2ecb6d62121d2958d3ea186cc88ce7 and below 81d54c766337b923eec26da0a13406760b091093 is affected.
- Version 8a02bdd50b2ecb6d62121d2958d3ea186cc88ce7 and below e8ee198bbc04a32d336e79160fde980e0235b39f is affected.
- Version 8a02bdd50b2ecb6d62121d2958d3ea186cc88ce7 and below 7cd9103283b26b917360ec99d7d2f2d761bcf1ab is affected.
- Version 2f6bf7917f55f9dae913193e49672b3598620eab is affected.
- Version 4.19.5 and below 4.20 is affected.
- Version 4.20 is affected.
- Before 4.20 is unaffected.
- Version 6.12.96, <= 6.12.* is unaffected.
- Version 6.18.39, <= 6.18.* is unaffected.
- Version 7.1.4, <= 7.1.* is unaffected.
- Version 7.2-rc2, <= * is unaffected.