{"id":"CVE-2023-53566","state":"PUBLISHED","title":"netfilter: nft_set_rbtree: fix null deref on element insertion","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_set_rbtree: fix null deref on element insertion\n\nThere is no guarantee that rb_prev() will not return NULL in nft_rbtree_gc_elem():\n\ngeneral protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN\nKASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]\n nft_add_set_elem+0x14b0/0x2990\n  nf_tables_newsetelem+0x528/0xb30\n\nFurthermore, there is a possible use-after-free while iterating,\n'node' can be free'd so we need to cache the next value to use.","publishedAt":"2025-10-04T15:17:08.598Z","updatedAt":"2026-10-15T21:41:30.987Z","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":"7ab87a326f20c52ff4d9972052d085be951c704b","status":"affected","lessThan":"b76db53ee8802ee5683f8cb401d7e2ec6f9b3d56","versionType":"git"},{"version":"181859bdfb9734aca449512fccaee4cacce64aed","status":"affected","lessThan":"899aa5638568abf5d69de7a7bb95e4615157375b","versionType":"git"},{"version":"4aacf3d78424293e318c616016865380b37b9cc5","status":"affected","lessThan":"3fa13203b6d90cc3a33af47b058739f92ab82eef","versionType":"git"},{"version":"2bf1435fa19d2c58054391b3bba40d5510a5758c","status":"affected","lessThan":"ec5caa765f7f6960011c919c9aeb1467940421f6","versionType":"git"},{"version":"318cb24a4c3fce8140afaf84e4d45fcb76fb280b","status":"affected","lessThan":"a836be60a3aabcedcd9c79f545d409ace1f20ba6","versionType":"git"},{"version":"c9e6978e2725a7d4b6cd23b2facd3f11422c0643","status":"affected","lessThan":"a337706c1fb35aac3f26b48aca80421bdbe1d33a","versionType":"git"},{"version":"c9e6978e2725a7d4b6cd23b2facd3f11422c0643","status":"affected","lessThan":"61ae320a29b0540c16931816299eb86bf2b66c08","versionType":"git"},{"version":"5.10.166","status":"affected","lessThan":"5.10.181","versionType":"semver"},{"version":"5.15.91","status":"affected","lessThan":"5.15.113","versionType":"semver"},{"version":"6.1.9","status":"affected","lessThan":"6.1.30","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nft_set_rbtree.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.2","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.2","versionType":"semver"},{"version":"5.10.181","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.113","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.30","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.3.4","status":"unaffected","lessThanOrEqual":"6.3.*","versionType":"semver"},{"version":"6.4","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nft_set_rbtree.c"]}],"references":["https://git.kernel.org/stable/c/b76db53ee8802ee5683f8cb401d7e2ec6f9b3d56","https://git.kernel.org/stable/c/899aa5638568abf5d69de7a7bb95e4615157375b","https://git.kernel.org/stable/c/3fa13203b6d90cc3a33af47b058739f92ab82eef","https://git.kernel.org/stable/c/ec5caa765f7f6960011c919c9aeb1467940421f6","https://git.kernel.org/stable/c/a836be60a3aabcedcd9c79f545d409ace1f20ba6","https://git.kernel.org/stable/c/a337706c1fb35aac3f26b48aca80421bdbe1d33a","https://git.kernel.org/stable/c/61ae320a29b0540c16931816299eb86bf2b66c08"],"weaknesses":[],"ingestedAt":"2026-10-29T20:06:33.064Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2023/53xxx/CVE-2023-53566.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2023-53566","state":"PUBLISHED","datePublished":"2025-10-04T15:17:08.598Z","dateUpdated":"2026-10-15T21:41:30.987Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-10-04T15:14:15.924Z"},"containers":{"cna":{"title":"netfilter: nft_set_rbtree: fix null deref on element insertion","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_set_rbtree: fix null deref on element insertion\n\nThere is no guarantee that rb_prev() will not return NULL in nft_rbtree_gc_elem():\n\ngeneral protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN\nKASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]\n nft_add_set_elem+0x14b0/0x2990\n  nf_tables_newsetelem+0x528/0xb30\n\nFurthermore, there is a possible use-after-free while iterating,\n'node' can be free'd so we need to cache the next value to use."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"7ab87a326f20c52ff4d9972052d085be951c704b","status":"affected","lessThan":"b76db53ee8802ee5683f8cb401d7e2ec6f9b3d56","versionType":"git"},{"version":"181859bdfb9734aca449512fccaee4cacce64aed","status":"affected","lessThan":"899aa5638568abf5d69de7a7bb95e4615157375b","versionType":"git"},{"version":"4aacf3d78424293e318c616016865380b37b9cc5","status":"affected","lessThan":"3fa13203b6d90cc3a33af47b058739f92ab82eef","versionType":"git"},{"version":"2bf1435fa19d2c58054391b3bba40d5510a5758c","status":"affected","lessThan":"ec5caa765f7f6960011c919c9aeb1467940421f6","versionType":"git"},{"version":"318cb24a4c3fce8140afaf84e4d45fcb76fb280b","status":"affected","lessThan":"a836be60a3aabcedcd9c79f545d409ace1f20ba6","versionType":"git"},{"version":"c9e6978e2725a7d4b6cd23b2facd3f11422c0643","status":"affected","lessThan":"a337706c1fb35aac3f26b48aca80421bdbe1d33a","versionType":"git"},{"version":"c9e6978e2725a7d4b6cd23b2facd3f11422c0643","status":"affected","lessThan":"61ae320a29b0540c16931816299eb86bf2b66c08","versionType":"git"},{"version":"5.10.166","status":"affected","lessThan":"5.10.181","versionType":"semver"},{"version":"5.15.91","status":"affected","lessThan":"5.15.113","versionType":"semver"},{"version":"6.1.9","status":"affected","lessThan":"6.1.30","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nft_set_rbtree.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.2","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.2","versionType":"semver"},{"version":"5.10.181","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.113","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.30","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.3.4","status":"unaffected","lessThanOrEqual":"6.3.*","versionType":"semver"},{"version":"6.4","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nft_set_rbtree.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/b76db53ee8802ee5683f8cb401d7e2ec6f9b3d56"},{"url":"https://git.kernel.org/stable/c/899aa5638568abf5d69de7a7bb95e4615157375b"},{"url":"https://git.kernel.org/stable/c/3fa13203b6d90cc3a33af47b058739f92ab82eef"},{"url":"https://git.kernel.org/stable/c/ec5caa765f7f6960011c919c9aeb1467940421f6"},{"url":"https://git.kernel.org/stable/c/a836be60a3aabcedcd9c79f545d409ace1f20ba6"},{"url":"https://git.kernel.org/stable/c/a337706c1fb35aac3f26b48aca80421bdbe1d33a"},{"url":"https://git.kernel.org/stable/c/61ae320a29b0540c16931816299eb86bf2b66c08"}],"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 vulnerable code is reached only through the nfnetlink/nftables netlink socket (NFT_MSG_NEWSETELEM), which requires local system access; there is no packet-processing path into nft_rbtree_gc_elem().\nAC:L - The attacker fully controls set contents, element timeouts, and insertion order, so making an expired element the leftmost rbtree node (rb_prev() == NULL) during the overlap walk is deterministic and needs no race or unpredictable memory layout.\nPR:L - Only CAP_NET_ADMIN in the network namespace is required, enforced via namespace-relative netlink_net_capable(), which any unprivileged user obtains with \"unshare -Urn\"; nftables and the rbtree set backend are fully netns-aware and autoloaded.\nUI:N - The attacker triggers the bug entirely from their own process by issuing netlink set-element operations; no victim action is involved.\nS:U - The corruption and crash occur within the kernel of the same host and security authority as the attacking task, with no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - The fix addresses a use-after-free during the tree walk (an rb_erase()'d, RCU-freed element is re-entered via rb_next()), and a UAF/double-free of nft_rbtree_elem objects gives the attacker control over reclaimed slab contents and thus a kernel memory read primitive.\nI:H - Beyond the crash, rb_erase() is invoked on an unvalidated rbe_prev (NULL or a wrong still-active element) and on already-erased nodes, producing attacker-influenced rbtree pointer writes and double nft_set_elem_destroy() — a classic heap-corruption primitive usable for control-flow hijack.\nA:H - The documented and readily reproducible outcome is a general protection fault / null-ptr-deref oops inside nft_add_set_elem() while holding the rbtree write lock and nftables commit mutex, panicking the kernel or wedging the netfilter subsystem."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T09:14:52.185Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.166","versionEndExcluding":"5.10.181"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.91","versionEndExcluding":"5.15.113"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.9","versionEndExcluding":"6.1.30"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.3.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.4"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP 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