{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-68206", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-12-16T13:41:40.255Z", "datePublished": "2025-12-16T13:48:33.763Z", "dateUpdated": "2026-08-05T12:10:11.706Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:10:11.706Z" }, "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." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - On an internet-facing gateway with the affected DNAT-before-helper rules, a remote FTP client can reach the path by requesting PASV/EPSV and causing the server reply to traverse netfilter.\nAC:L - Once the affected FTP NAT configuration exists, a length-changing payload rewrite triggers the flaw deterministically. No race, timing, or attacker-uncontrollable memory layout is required.\nPR:N - CAP_NET_ADMIN is required only for the operator to install the ruleset, not for exploitation. A remote client of an anonymous FTP service needs no account or kernel privilege.\nUI:N - No victim action is required after the FTP service and NAT rules are deployed; the network protocol exchange triggers the vulnerable path.\nS:U - The impact remains within the gateway's kernel and system security authority, without crossing a VM, IOMMU, or comparable boundary.\nC:N - The missing extension is detected before dereference, and the path performs no out-of-bounds read, stale-memory access, or information disclosure.\nI:N - There is no memory corruption or attacker-controlled write primitive. The intended FTP payload rewrite merely becomes TCP-sequence-desynchronized because its adjustment state is not recorded.\nA:H - The path reliably executes WARN_ONCE, which causes a complete kernel panic on reasonable panic_on_warn deployments. Otherwise, the absent sequence translation disrupts affected FTP sessions." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/netfilter/nft_ct.c" ], "versions": [ { "version": "1a64edf54f55d7956cf5a0d95898bc1f84f9b818", "lessThan": "83273af0b60c093ba0085c205864d8542e1b1653", "status": "affected", "versionType": "git" }, { "version": "1a64edf54f55d7956cf5a0d95898bc1f84f9b818", "lessThan": "b19492c25eff04852e0cb58f9bb8238b6695ed2d", "status": "affected", "versionType": "git" }, { "version": "1a64edf54f55d7956cf5a0d95898bc1f84f9b818", "lessThan": "4de80f0dc3868408dd7fe9817e507123c9dd8bb0", "status": "affected", "versionType": "git" }, { "version": "1a64edf54f55d7956cf5a0d95898bc1f84f9b818", "lessThan": "b477ef7fa612fa45b6b3134d90d1eeb09396500a", "status": "affected", "versionType": "git" }, { "version": "1a64edf54f55d7956cf5a0d95898bc1f84f9b818", "lessThan": "4ab2cd906e4e1a19ddbda6eb532851b0e9cda110", "status": "affected", "versionType": "git" }, { "version": "1a64edf54f55d7956cf5a0d95898bc1f84f9b818", "lessThan": "2b52d89cbbb0dbe3e948d8d9a91e704316dccfe6", "status": "affected", "versionType": "git" }, { "version": "1a64edf54f55d7956cf5a0d95898bc1f84f9b818", "lessThan": "90918e3b6404c2a37837b8f11692471b4c512de2", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/netfilter/nft_ct.c" ], "versions": [ { "version": "4.12", "status": "affected" }, { "version": "0", "lessThan": "4.12", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.253", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.203", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.167", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.130", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.64", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17.9", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "5.10.253" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "5.15.203" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "6.1.167" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "6.6.130" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "6.12.64" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "6.17.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "6.18" } ] } ] } ], "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" } }, "adp": [ { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-07-14T12:43:48.874Z" }, "affected": [ { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", 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