{"id":"CVE-2025-40206","summary":"netfilter: nft_objref: validate objref and objrefmap expressions","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_objref: validate objref and objrefmap expressions\n\nReferencing a synproxy stateful object from OUTPUT hook causes kernel\ncrash due to infinite recursive calls:\n\nBUG: TASK stack guard page was hit at 000000008bda5b8c (stack is 000000003ab1c4a5..00000000494d8b12)\n[...]\nCall Trace:\n __find_rr_leaf+0x99/0x230\n fib6_table_lookup+0x13b/0x2d0\n ip6_pol_route+0xa4/0x400\n fib6_rule_lookup+0x156/0x240\n ip6_route_output_flags+0xc6/0x150\n __nf_ip6_route+0x23/0x50\n synproxy_send_tcp_ipv6+0x106/0x200\n synproxy_send_client_synack_ipv6+0x1aa/0x1f0\n nft_synproxy_do_eval+0x263/0x310\n nft_do_chain+0x5a8/0x5f0 [nf_tables\n nft_do_chain_inet+0x98/0x110\n nf_hook_slow+0x43/0xc0\n __ip6_local_out+0xf0/0x170\n ip6_local_out+0x17/0x70\n synproxy_send_tcp_ipv6+0x1a2/0x200\n synproxy_send_client_synack_ipv6+0x1aa/0x1f0\n[...]\n\nImplement objref and objrefmap expression validate functions.\n\nCurrently, only NFT_OBJECT_SYNPROXY object type requires validation.\nThis will also handle a jump to a chain using a synproxy object from the\nOUTPUT hook.\n\nNow when trying to reference a synproxy object in the OUTPUT hook, nft\nwill produce the following error:\n\nsynproxy_crash.nft: Error: Could not process rule: Operation not supported\n  synproxy name mysynproxy\n  ^^^^^^^^^^^^^^^^^^^^^^^^","modified":"2026-04-02T12:48:19.439413Z","published":"2025-11-12T21:56:35.675Z","related":["SUSE-SU-2025:4393-1","SUSE-SU-2025:4422-1","SUSE-SU-2025:4505-1","SUSE-SU-2025:4516-1","SUSE-SU-2025:4517-1","SUSE-SU-2025:4521-1","SUSE-SU-2026:20012-1","SUSE-SU-2026:20015-1","SUSE-SU-2026:20021-1","SUSE-SU-2026:20039-1","SUSE-SU-2026:20059-1","SUSE-SU-2026:20473-1","SUSE-SU-2026:20496-1","openSUSE-SU-2025:20172-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40206.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0028e0134c64d9ed21728341a74fcfc59cd0f944"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4c1cf72ec10be5a9ad264650cadffa1fbce6fabd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7ea55a44493a5a36c3b3293b88bbe4841f9dbaf0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f359b809d54c6e3dd1d039b97e0b68390b0e53e4"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40206.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-40206"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"ee394f96ad7517fbc0de9106dcc7ce9efb14f264"},{"fixed":"0028e0134c64d9ed21728341a74fcfc59cd0f944"},{"fixed":"7ea55a44493a5a36c3b3293b88bbe4841f9dbaf0"},{"fixed":"4c1cf72ec10be5a9ad264650cadffa1fbce6fabd"},{"fixed":"f359b809d54c6e3dd1d039b97e0b68390b0e53e4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40206.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.4.0"},{"fixed":"6.6.113"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.54"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.17.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40206.json"}}],"schema_version":"1.7.5"}