{"id":"CVE-2026-72251","revision":"6887c93a84c1405180609be33eeebdae","records":[{"revision":"6887c93a84c1405180609be33eeebdae","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-72251","aliases":[],"title":"netfilter: nf_nat_sip: reload possible stale data pointer","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_nat_sip: reload possible stale data pointer\n\nquoting sashiko:\n ------------------------------------------------------------------------\n [..] noticed a potential memory bug and header corruption involving the\n SIP NAT helper.\n\n In net/netfilter/nf_nat_sip.c:nf_nat_sip():\n\tif (skb_ensure_writable(skb, skb->len)) {\n\t\tnf_ct_helper_log(skb, ct, \"cannot mangle packet\");\n\t\treturn NF_DROP;\n\t}\n\tuh = (void *)skb->data + protoff;\n\tuh->dest = ct_sip_info->forced_dport;\n\tif (!nf_nat_mangle_udp_packet(skb, ct, ctinfo, protoff,\n\t\t\t\t      0, 0, NULL, 0)) {\n\n If a cloned or fragmented SKB is reallocated by skb_ensure_writable(), the\n old data buffer is freed. However, nf_nat_sip() fails to update *dptr to\n point to the new buffer.\n\n It also appears to use nf_nat_mangle_udp_packet() on what could be a TCP\n packet, which would overwrite the sequence number with a checksum update.\n ------------------------------------------------------------------------\n\nnf_conntrack_sip linerizes skbs, hence no fragmented skb can be seen.\nBut clones are possible, so rebuild dptr.\n\nDisable nf_nat_mangle_udp_packet() branch for TCP streams.\nIt doesn't look like this can ever happen, else we should have received\nbug reports about this, so just check the conntrack is UDP and drop\notherwise.\n\nThe calling conntrack_sip set ->forced_dport for SIP_HDR_VIA_UDP messages,\nso I don't think this is ever expected to be true for a TCP stream.","state":0,"publishedAt":"2026-08-15T05:54:39.983+00:00","modifiedAt":"2026-10-16T18:55:13.187+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/netfilter/nf_nat_sip.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"7266507d89991fa1e989283e4e032c6d9357fe26\",\n                            \"lessThan\": \"bded21a4bf9bf86a79148be735723a97ca9a7532\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7266507d89991fa1e989283e4e032c6d9357fe26\",\n                            \"lessThan\": \"dc11f26685aa850f237226f0f463647aea58ab7c\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7266507d89991fa1e989283e4e032c6d9357fe26\",\n                            \"lessThan\": \"e38143c9b477f2968024c47c647dd4456a40aff1\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7266507d89991fa1e989283e4e032c6d9357fe26\",\n                            \"lessThan\": \"57e4e29644ec054d7021d296407e7ddd844afea2\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7266507d89991fa1e989283e4e032c6d9357fe26\",\n                            \"lessThan\": \"eae9c6ccb5af69c713a65f8ae219f5c1aa32cd17\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7266507d89991fa1e989283e4e032c6d9357fe26\",\n                            \"lessThan\": \"2bcf2c5052fb5e73e255140ab43f056aef409c27\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7266507d89991fa1e989283e4e032c6d9357fe26\",\n                            \"lessThan\": \"0e76e3e886cc9ee027337d5ad39cb96f57b7bdc7\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7266507d89991fa1e989283e4e032c6d9357fe26\",\n                            \"lessThan\": \"77e43bcb7ec177e293a5c3f1b91a2c5aebfb6c68\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/netfilter/nf_nat_sip.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"3.9\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"3.9\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.261\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.212\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.178\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.145\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.97\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.40\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.1.5\",\n                            \"lessThanOrEqual\": \"7.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://git.kernel.org/stable/c/bded21a4bf9bf86a79148be735723a97ca9a7532","https://git.kernel.org/stable/c/dc11f26685aa850f237226f0f463647aea58ab7c","https://git.kernel.org/stable/c/e38143c9b477f2968024c47c647dd4456a40aff1","https://git.kernel.org/stable/c/57e4e29644ec054d7021d296407e7ddd844afea2","https://git.kernel.org/stable/c/eae9c6ccb5af69c713a65f8ae219f5c1aa32cd17","https://git.kernel.org/stable/c/2bcf2c5052fb5e73e255140ab43f056aef409c27","https://git.kernel.org/stable/c/0e76e3e886cc9ee027337d5ad39cb96f57b7bdc7","https://git.kernel.org/stable/c/77e43bcb7ec177e293a5c3f1b91a2c5aebfb6c68"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72251","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-72251","identifiers":["CVE-2026-72251"]},"retained":false,"historicalAffected":[]}],"coverage":[]}