ghsa-3xw5-26jc-pqjh
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nft_objref: validate objref and objrefmap expressions
Referencing a synproxy stateful object from OUTPUT hook causes kernel crash due to infinite recursive calls:
BUG: TASK stack guard page was hit at 000000008bda5b8c (stack is 000000003ab1c4a5..00000000494d8b12) [...] Call Trace: __find_rr_leaf+0x99/0x230 fib6_table_lookup+0x13b/0x2d0 ip6_pol_route+0xa4/0x400 fib6_rule_lookup+0x156/0x240 ip6_route_output_flags+0xc6/0x150 __nf_ip6_route+0x23/0x50 synproxy_send_tcp_ipv6+0x106/0x200 synproxy_send_client_synack_ipv6+0x1aa/0x1f0 nft_synproxy_do_eval+0x263/0x310 nft_do_chain+0x5a8/0x5f0 [nf_tables nft_do_chain_inet+0x98/0x110 nf_hook_slow+0x43/0xc0 __ip6_local_out+0xf0/0x170 ip6_local_out+0x17/0x70 synproxy_send_tcp_ipv6+0x1a2/0x200 synproxy_send_client_synack_ipv6+0x1aa/0x1f0 [...]
Implement objref and objrefmap expression validate functions.
Currently, only NFT_OBJECT_SYNPROXY object type requires validation. This will also handle a jump to a chain using a synproxy object from the OUTPUT hook.
Now when trying to reference a synproxy object in the OUTPUT hook, nft will produce the following error:
synproxy_crash.nft: Error: Could not process rule: Operation not supported synproxy name mysynproxy ^^^^^^^^^^^^^^^^^^^^^^^^
{
"affected": [],
"aliases": [
"CVE-2025-40206"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-11-12T22:15:47Z",
"severity": null
},
"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 ^^^^^^^^^^^^^^^^^^^^^^^^",
"id": "GHSA-3xw5-26jc-pqjh",
"modified": "2025-11-13T00:30:18Z",
"published": "2025-11-13T00:30:18Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-40206"
},
{
"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"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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