{"api_version":"1","generated_at":"2026-04-23T06:19:37+00:00","cve":"CVE-2025-68206","urls":{"html":"https://cve.report/CVE-2025-68206","api":"https://cve.report/api/cve/CVE-2025-68206.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2025-68206","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2025-68206"},"summary":{"title":"netfilter: nft_ct: add seqadj extension for natted connections","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_ct: add seqadj extension for natted connections\n\nSequence adjustment may be required for FTP traffic with PASV/EPSV modes.\ndue to need to re-write packet payload (IP, port) on the ftp control\nconnection. This can require changes to the TCP length and expected\nseq / ack_seq.\n\nThe easiest way to reproduce this issue is with PASV mode.\nExample ruleset:\ntable inet ftp_nat {\n        ct helper ftp_helper {\n                type \"ftp\" protocol tcp\n                l3proto inet\n        }\n\n        chain prerouting {\n                type filter hook prerouting priority 0; policy accept;\n                tcp dport 21 ct state new ct helper set \"ftp_helper\"\n        }\n}\ntable ip nat {\n        chain prerouting {\n                type nat hook prerouting priority -100; policy accept;\n                tcp dport 21 dnat ip prefix to ip daddr map {\n\t\t\t192.168.100.1 : 192.168.13.2/32 }\n        }\n\n        chain postrouting {\n                type nat hook postrouting priority 100 ; policy accept;\n                tcp sport 21 snat ip prefix to ip saddr map {\n\t\t\t192.168.13.2 : 192.168.100.1/32 }\n        }\n}\n\nNote that the ftp helper gets assigned *after* the dnat setup.\n\nThe inverse (nat after helper assign) is handled by an existing\ncheck in nf_nat_setup_info() and will not show the problem.\n\nTopoloy:\n\n +-------------------+     +----------------------------------+\n | FTP: 192.168.13.2 | <-> | NAT: 192.168.13.3, 192.168.100.1 |\n +-------------------+     +----------------------------------+\n                                      |\n                         +-----------------------+\n                         | Client: 192.168.100.2 |\n                         +-----------------------+\n\nftp nat changes do not work as expected in this case:\nConnected to 192.168.100.1.\n[..]\nftp> epsv\nEPSV/EPRT on IPv4 off.\nftp> ls\n227 Entering passive mode (192,168,100,1,209,129).\n421 Service not available, remote server has closed connection.\n\nKernel logs:\nMissing nfct_seqadj_ext_add() setup call\nWARNING: CPU: 1 PID: 0 at net/netfilter/nf_conntrack_seqadj.c:41\n[..]\n __nf_nat_mangle_tcp_packet+0x100/0x160 [nf_nat]\n nf_nat_ftp+0x142/0x280 [nf_nat_ftp]\n help+0x4d1/0x880 [nf_conntrack_ftp]\n nf_confirm+0x122/0x2e0 [nf_conntrack]\n nf_hook_slow+0x3c/0xb0\n ..\n\nFix this by adding the required extension when a conntrack helper is assigned\nto a connection that has a nat binding.","state":"PUBLISHED","assigner":"Linux","published_at":"2025-12-16 14:15:53","updated_at":"2026-04-18 09:16:12"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/b19492c25eff04852e0cb58f9bb8238b6695ed2d","name":"https://git.kernel.org/stable/c/b19492c25eff04852e0cb58f9bb8238b6695ed2d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4ab2cd906e4e1a19ddbda6eb532851b0e9cda110","name":"https://git.kernel.org/stable/c/4ab2cd906e4e1a19ddbda6eb532851b0e9cda110","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/90918e3b6404c2a37837b8f11692471b4c512de2","name":"https://git.kernel.org/stable/c/90918e3b6404c2a37837b8f11692471b4c512de2","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/b477ef7fa612fa45b6b3134d90d1eeb09396500a","name":"https://git.kernel.org/stable/c/b477ef7fa612fa45b6b3134d90d1eeb09396500a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/83273af0b60c093ba0085c205864d8542e1b1653","name":"https://git.kernel.org/stable/c/83273af0b60c093ba0085c205864d8542e1b1653","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4de80f0dc3868408dd7fe9817e507123c9dd8bb0","name":"https://git.kernel.org/stable/c/4de80f0dc3868408dd7fe9817e507123c9dd8bb0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2b52d89cbbb0dbe3e948d8d9a91e704316dccfe6","name":"https://git.kernel.org/stable/c/2b52d89cbbb0dbe3e948d8d9a91e704316dccfe6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2025-68206","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-68206","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1a64edf54f55d7956cf5a0d95898bc1f84f9b818 83273af0b60c093ba0085c205864d8542e1b1653 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1a64edf54f55d7956cf5a0d95898bc1f84f9b818 b19492c25eff04852e0cb58f9bb8238b6695ed2d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1a64edf54f55d7956cf5a0d95898bc1f84f9b818 4de80f0dc3868408dd7fe9817e507123c9dd8bb0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1a64edf54f55d7956cf5a0d95898bc1f84f9b818 b477ef7fa612fa45b6b3134d90d1eeb09396500a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1a64edf54f55d7956cf5a0d95898bc1f84f9b818 4ab2cd906e4e1a19ddbda6eb532851b0e9cda110 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1a64edf54f55d7956cf5a0d95898bc1f84f9b818 2b52d89cbbb0dbe3e948d8d9a91e704316dccfe6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1a64edf54f55d7956cf5a0d95898bc1f84f9b818 90918e3b6404c2a37837b8f11692471b4c512de2 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.12","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 4.12 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.10.253 5.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.203 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.167 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.130 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.64 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.17.9 6.17.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2025","cve_id":"68206","cve":"CVE-2025-68206","epss":"0.000680000","percentile":"0.210040000","score_date":"2026-04-21","updated_at":"2026-04-22 00:07:40"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/netfilter/nft_ct.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"83273af0b60c093ba0085c205864d8542e1b1653","status":"affected","version":"1a64edf54f55d7956cf5a0d95898bc1f84f9b818","versionType":"git"},{"lessThan":"b19492c25eff04852e0cb58f9bb8238b6695ed2d","status":"affected","version":"1a64edf54f55d7956cf5a0d95898bc1f84f9b818","versionType":"git"},{"lessThan":"4de80f0dc3868408dd7fe9817e507123c9dd8bb0","status":"affected","version":"1a64edf54f55d7956cf5a0d95898bc1f84f9b818","versionType":"git"},{"lessThan":"b477ef7fa612fa45b6b3134d90d1eeb09396500a","status":"affected","version":"1a64edf54f55d7956cf5a0d95898bc1f84f9b818","versionType":"git"},{"lessThan":"4ab2cd906e4e1a19ddbda6eb532851b0e9cda110","status":"affected","version":"1a64edf54f55d7956cf5a0d95898bc1f84f9b818","versionType":"git"},{"lessThan":"2b52d89cbbb0dbe3e948d8d9a91e704316dccfe6","status":"affected","version":"1a64edf54f55d7956cf5a0d95898bc1f84f9b818","versionType":"git"},{"lessThan":"90918e3b6404c2a37837b8f11692471b4c512de2","status":"affected","version":"1a64edf54f55d7956cf5a0d95898bc1f84f9b818","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/netfilter/nft_ct.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"4.12"},{"lessThan":"4.12","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.253","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.203","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.167","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.130","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.64","versionType":"semver"},{"lessThanOrEqual":"6.17.*","status":"unaffected","version":"6.17.9","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"6.18","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.253","versionStartIncluding":"4.12","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.203","versionStartIncluding":"4.12","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.167","versionStartIncluding":"4.12","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.130","versionStartIncluding":"4.12","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.64","versionStartIncluding":"4.12","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.17.9","versionStartIncluding":"4.12","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18","versionStartIncluding":"4.12","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_ct: add seqadj extension for natted connections\n\nSequence adjustment may be required for FTP traffic with PASV/EPSV modes.\ndue to need to re-write packet payload (IP, port) on the ftp control\nconnection. This can require changes to the TCP length and expected\nseq / ack_seq.\n\nThe easiest way to reproduce this issue is with PASV mode.\nExample ruleset:\ntable inet ftp_nat {\n        ct helper ftp_helper {\n                type \"ftp\" protocol tcp\n                l3proto inet\n        }\n\n        chain prerouting {\n                type filter hook prerouting priority 0; policy accept;\n                tcp dport 21 ct state new ct helper set \"ftp_helper\"\n        }\n}\ntable ip nat {\n        chain prerouting {\n                type nat hook prerouting priority -100; policy accept;\n                tcp dport 21 dnat ip prefix to ip daddr map {\n\t\t\t192.168.100.1 : 192.168.13.2/32 }\n        }\n\n        chain postrouting {\n                type nat hook postrouting priority 100 ; policy accept;\n                tcp sport 21 snat ip prefix to ip saddr map {\n\t\t\t192.168.13.2 : 192.168.100.1/32 }\n        }\n}\n\nNote that the ftp helper gets assigned *after* the dnat setup.\n\nThe inverse (nat after helper assign) is handled by an existing\ncheck in nf_nat_setup_info() and will not show the problem.\n\nTopoloy:\n\n +-------------------+     +----------------------------------+\n | FTP: 192.168.13.2 | <-> | NAT: 192.168.13.3, 192.168.100.1 |\n +-------------------+     +----------------------------------+\n                                      |\n                         +-----------------------+\n                         | Client: 192.168.100.2 |\n                         +-----------------------+\n\nftp nat changes do not work as expected in this case:\nConnected to 192.168.100.1.\n[..]\nftp> epsv\nEPSV/EPRT on IPv4 off.\nftp> ls\n227 Entering passive mode (192,168,100,1,209,129).\n421 Service not available, remote server has closed connection.\n\nKernel logs:\nMissing nfct_seqadj_ext_add() setup call\nWARNING: CPU: 1 PID: 0 at net/netfilter/nf_conntrack_seqadj.c:41\n[..]\n __nf_nat_mangle_tcp_packet+0x100/0x160 [nf_nat]\n nf_nat_ftp+0x142/0x280 [nf_nat_ftp]\n help+0x4d1/0x880 [nf_conntrack_ftp]\n nf_confirm+0x122/0x2e0 [nf_conntrack]\n nf_hook_slow+0x3c/0xb0\n ..\n\nFix this by adding the required extension when a conntrack helper is assigned\nto a connection that has a nat binding."}],"providerMetadata":{"dateUpdated":"2026-04-18T08:57:10.560Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/83273af0b60c093ba0085c205864d8542e1b1653"},{"url":"https://git.kernel.org/stable/c/b19492c25eff04852e0cb58f9bb8238b6695ed2d"},{"url":"https://git.kernel.org/stable/c/4de80f0dc3868408dd7fe9817e507123c9dd8bb0"},{"url":"https://git.kernel.org/stable/c/b477ef7fa612fa45b6b3134d90d1eeb09396500a"},{"url":"https://git.kernel.org/stable/c/4ab2cd906e4e1a19ddbda6eb532851b0e9cda110"},{"url":"https://git.kernel.org/stable/c/2b52d89cbbb0dbe3e948d8d9a91e704316dccfe6"},{"url":"https://git.kernel.org/stable/c/90918e3b6404c2a37837b8f11692471b4c512de2"}],"title":"netfilter: nft_ct: add seqadj extension for natted connections","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2025-68206","datePublished":"2025-12-16T13:48:33.763Z","dateReserved":"2025-12-16T13:41:40.255Z","dateUpdated":"2026-04-18T08:57:10.560Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2025-12-16 14:15:53","lastModifiedDate":"2026-04-18 09:16:12","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2025","CveId":"68206","Ordinal":"1","Title":"netfilter: nft_ct: add seqadj extension for natted connections","CVE":"CVE-2025-68206","Year":"2025"},"notes":[{"CveYear":"2025","CveId":"68206","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_ct: add seqadj extension for natted connections\n\nSequence adjustment may be required for FTP traffic with PASV/EPSV modes.\ndue to need to re-write packet payload (IP, port) on the ftp control\nconnection. This can require changes to the TCP length and expected\nseq / ack_seq.\n\nThe easiest way to reproduce this issue is with PASV mode.\nExample ruleset:\ntable inet ftp_nat {\n        ct helper ftp_helper {\n                type \"ftp\" protocol tcp\n                l3proto inet\n        }\n\n        chain prerouting {\n                type filter hook prerouting priority 0; policy accept;\n                tcp dport 21 ct state new ct helper set \"ftp_helper\"\n        }\n}\ntable ip nat {\n        chain prerouting {\n                type nat hook prerouting priority -100; policy accept;\n                tcp dport 21 dnat ip prefix to ip daddr map {\n\t\t\t192.168.100.1 : 192.168.13.2/32 }\n        }\n\n        chain postrouting {\n                type nat hook postrouting priority 100 ; policy accept;\n                tcp sport 21 snat ip prefix to ip saddr map {\n\t\t\t192.168.13.2 : 192.168.100.1/32 }\n        }\n}\n\nNote that the ftp helper gets assigned *after* the dnat setup.\n\nThe inverse (nat after helper assign) is handled by an existing\ncheck in nf_nat_setup_info() and will not show the problem.\n\nTopoloy:\n\n +-------------------+     +----------------------------------+\n | FTP: 192.168.13.2 | <-> | NAT: 192.168.13.3, 192.168.100.1 |\n +-------------------+     +----------------------------------+\n                                      |\n                         +-----------------------+\n                         | Client: 192.168.100.2 |\n                         +-----------------------+\n\nftp nat changes do not work as expected in this case:\nConnected to 192.168.100.1.\n[..]\nftp> epsv\nEPSV/EPRT on IPv4 off.\nftp> ls\n227 Entering passive mode (192,168,100,1,209,129).\n421 Service not available, remote server has closed connection.\n\nKernel logs:\nMissing nfct_seqadj_ext_add() setup call\nWARNING: CPU: 1 PID: 0 at net/netfilter/nf_conntrack_seqadj.c:41\n[..]\n __nf_nat_mangle_tcp_packet+0x100/0x160 [nf_nat]\n nf_nat_ftp+0x142/0x280 [nf_nat_ftp]\n help+0x4d1/0x880 [nf_conntrack_ftp]\n nf_confirm+0x122/0x2e0 [nf_conntrack]\n nf_hook_slow+0x3c/0xb0\n ..\n\nFix this by adding the required extension when a conntrack helper is assigned\nto a connection that has a nat binding.","Type":"Description","Title":"netfilter: nft_ct: add seqadj extension for natted connections"}]}}}