{"id":"CVE-2026-72435","state":"PUBLISHED","title":"netfilter: ipset: fix order of kfree_rcu() and rcu_assign_pointer()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ipset: fix order of kfree_rcu() and rcu_assign_pointer()\n\nSashiko pointed out that kfree_rcu() was called before\nrcu_assign_pointer() in handling the comment extension.\nFix the order so that rcu_assign_pointer() called first.","publishedAt":"2026-08-15T05:56:49.402Z","updatedAt":"2026-10-16T18:55:23.893Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"b57b2d1fa53fe8563bdfc66a33b844463b9af285","status":"affected","lessThan":"c9787d7c24ffd83019f379455e1b97fb4f0f75eb","versionType":"git"},{"version":"b57b2d1fa53fe8563bdfc66a33b844463b9af285","status":"affected","lessThan":"6e98407cb94e035bba98956adc9096a76d8b2a9f","versionType":"git"},{"version":"b57b2d1fa53fe8563bdfc66a33b844463b9af285","status":"affected","lessThan":"50b70f56f3baaff46599f59b2d93fa2540120776","versionType":"git"},{"version":"b57b2d1fa53fe8563bdfc66a33b844463b9af285","status":"affected","lessThan":"d01b4b471f0fc5c396af62845e972ccf99cee29a","versionType":"git"},{"version":"b57b2d1fa53fe8563bdfc66a33b844463b9af285","status":"affected","lessThan":"fcb565966534909377a16be5f7b065db2e25c8b5","versionType":"git"},{"version":"b57b2d1fa53fe8563bdfc66a33b844463b9af285","status":"affected","lessThan":"8087bb360a936a6314d22b567e4b861656943eb6","versionType":"git"},{"version":"b57b2d1fa53fe8563bdfc66a33b844463b9af285","status":"affected","lessThan":"93a775fd67f3ef34949a9523bfa69403ee74efdd","versionType":"git"},{"version":"b57b2d1fa53fe8563bdfc66a33b844463b9af285","status":"affected","lessThan":"3ca9982a8882470aa0ac4e8bb9a552b181d1efcd","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/ipset/ip_set_core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.2","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.2","versionType":"semver"},{"version":"5.10.261","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.212","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/ipset/ip_set_core.c"]}],"references":["https://git.kernel.org/stable/c/c9787d7c24ffd83019f379455e1b97fb4f0f75eb","https://git.kernel.org/stable/c/6e98407cb94e035bba98956adc9096a76d8b2a9f","https://git.kernel.org/stable/c/50b70f56f3baaff46599f59b2d93fa2540120776","https://git.kernel.org/stable/c/d01b4b471f0fc5c396af62845e972ccf99cee29a","https://git.kernel.org/stable/c/fcb565966534909377a16be5f7b065db2e25c8b5","https://git.kernel.org/stable/c/8087bb360a936a6314d22b567e4b861656943eb6","https://git.kernel.org/stable/c/93a775fd67f3ef34949a9523bfa69403ee74efdd","https://git.kernel.org/stable/c/3ca9982a8882470aa0ac4e8bb9a552b181d1efcd"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/72xxx/CVE-2026-72435.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-72435","state":"PUBLISHED","datePublished":"2026-08-15T05:56:49.402Z","dateUpdated":"2026-10-16T18:55:23.893Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-09T03:40:39.929Z"},"containers":{"cna":{"title":"netfilter: ipset: fix order of kfree_rcu() and rcu_assign_pointer()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ipset: fix order of kfree_rcu() and rcu_assign_pointer()\n\nSashiko pointed out that kfree_rcu() was called before\nrcu_assign_pointer() in handling the comment extension.\nFix the order so that rcu_assign_pointer() called first."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"b57b2d1fa53fe8563bdfc66a33b844463b9af285","status":"affected","lessThan":"c9787d7c24ffd83019f379455e1b97fb4f0f75eb","versionType":"git"},{"version":"b57b2d1fa53fe8563bdfc66a33b844463b9af285","status":"affected","lessThan":"6e98407cb94e035bba98956adc9096a76d8b2a9f","versionType":"git"},{"version":"b57b2d1fa53fe8563bdfc66a33b844463b9af285","status":"affected","lessThan":"50b70f56f3baaff46599f59b2d93fa2540120776","versionType":"git"},{"version":"b57b2d1fa53fe8563bdfc66a33b844463b9af285","status":"affected","lessThan":"d01b4b471f0fc5c396af62845e972ccf99cee29a","versionType":"git"},{"version":"b57b2d1fa53fe8563bdfc66a33b844463b9af285","status":"affected","lessThan":"fcb565966534909377a16be5f7b065db2e25c8b5","versionType":"git"},{"version":"b57b2d1fa53fe8563bdfc66a33b844463b9af285","status":"affected","lessThan":"8087bb360a936a6314d22b567e4b861656943eb6","versionType":"git"},{"version":"b57b2d1fa53fe8563bdfc66a33b844463b9af285","status":"affected","lessThan":"93a775fd67f3ef34949a9523bfa69403ee74efdd","versionType":"git"},{"version":"b57b2d1fa53fe8563bdfc66a33b844463b9af285","status":"affected","lessThan":"3ca9982a8882470aa0ac4e8bb9a552b181d1efcd","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/ipset/ip_set_core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.2","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.2","versionType":"semver"},{"version":"5.10.261","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.212","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/ipset/ip_set_core.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/c9787d7c24ffd83019f379455e1b97fb4f0f75eb"},{"url":"https://git.kernel.org/stable/c/6e98407cb94e035bba98956adc9096a76d8b2a9f"},{"url":"https://git.kernel.org/stable/c/50b70f56f3baaff46599f59b2d93fa2540120776"},{"url":"https://git.kernel.org/stable/c/d01b4b471f0fc5c396af62845e972ccf99cee29a"},{"url":"https://git.kernel.org/stable/c/fcb565966534909377a16be5f7b065db2e25c8b5"},{"url":"https://git.kernel.org/stable/c/8087bb360a936a6314d22b567e4b861656943eb6"},{"url":"https://git.kernel.org/stable/c/93a775fd67f3ef34949a9523bfa69403ee74efdd"},{"url":"https://git.kernel.org/stable/c/3ca9982a8882470aa0ac4e8bb9a552b181d1efcd"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The bug is reached only through nfnetlink IPSET commands (ADD/DEL/LIST/SAVE) on NETLINK_GENERIC; nfnetlink_rcv() requires CAP_NET_ADMIN and no remote packet path feeds comment free/replace, so kernel CNA guidance treats netfilter/ipset netlink as Local.\nAC:L - LIST/SAVE dump runs asynchronously without holding the nfnl mutex while mtype_list holds rcu_read_lock and calls ip_set_put_comment; an attacker with CAP_NET_ADMIN can concurrently issue ADD/--exist comment replacement, DEL/flush, or timeout GC to hit the kfree_rcu-before-NULL ordering reliably.\nPR:L - nfnetlink_rcv() gates every ipset command on netlink_net_capable(skb, CAP_NET_ADMIN), which resolves to ns_capable(sock_net()->user_ns, CAP_NET_ADMIN); unprivileged users obtain this inside a user/network namespace via unshare -Urn and fully control per-netns ipset configuration.\nUI:N - Exploitation is fully attacker-driven through netlink: create a comment-enabled set, start LIST/SAVE dump, and concurrently add/delete/flush elements or let timeout GC run; no victim click, mount, or other deliberate action is required beyond ordinary local control.\nS:U - The RCU use-after-free corrupts kernel heap memory and can yield host privilege escalation or crash, but impact stays within the same kernel security authority and does not cross VM/host, container/host, or IOMMU boundaries.\nC:H - Calling kfree_rcu() before rcu_assign_pointer(NULL) lets dump readers under rcu_read_lock still rcu_dereference(comment->c) and nla_put_string() reads freed ip_set_comment_rcu kmalloc memory—a classic UAF read usable for arbitrary kernel disclosure with heap grooming.\nI:H - Concurrent free and replacement of RCU-managed comment objects lets an attacker reclaim and control freed slab memory, providing standard paths to arbitrary kernel writes, metadata corruption, and control-flow hijack rather than a bounded or crash-only integrity effect.\nA:H - Stale comment pointer dereference during dump or subsequent slab reuse can immediately kernel-oops or panic the host, and the underlying UAF heap corruption can crash or hang the system even when full exploitation is not 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