{"id":"CVE-2026-99201","revision":"78412d84f40f40ec8097ed34bdb7187b","records":[{"revision":"78412d84f40f40ec8097ed34bdb7187b","observedAt":"2026-10-28T11:27:43.363+00:00","statement":{"source":"cve-program","id":"CVE-2026-99201","aliases":[],"title":"netlink: avoid hashing the network namespace pointer","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetlink: avoid hashing the network namespace pointer\n\nThe netlink rhashtable key includes a raw struct net pointer and a\nuser-controlled port ID. Both /proc/net/netlink and socket diagnostics\nexpose the table's bucket order. By binding and rebinding chosen\nNETLINK_USERSOCK port IDs, an unprivileged reader can distinguish equal\nbuckets and recover the low bits of the Jenkins hash. Its 32-bit seed\nand the limited set of kernel-image slides can then be searched offline\nto recover the address of init_net.\n\nUse the namespace's unique, non-address net_cookie in the comparison\nkey instead. It is assigned before the per-net initializers run and\nremains unchanged for the namespace's lifetime. The lookup key and\nobject hash are still built by netlink_compare_arg_init(), keeping\nlookup, insertion, removal and rehashing consistent while preserving\nnamespace separation. Neither public table walker needs to change.\n\nReading the socket's namespace cookie in netlink_compare() is safe\nunder RCU, including during namespace teardown. netlink_release()\nremoves the socket from the hash table and defers its final put with\ncall_rcu(). cleanup_net() runs the per-net exit methods and waits for\noutstanding RCU callbacks with rcu_barrier() before freeing namespace\nstorage.\n\nUnlike ns.ns_id, net_cookie is also available and initialized during\nsetup_net() in older stable kernels, making the change straightforward\nto backport to v5.15 and later.","state":0,"publishedAt":"2026-10-28T10:35:56.069+00:00","modifiedAt":"2026-10-28T10:35:56.069+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/netlink/af_netlink.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"c428ecd1a21f1457ca3beb4df71b8a079c410e41\",\n                            \"lessThan\": \"bdd55b8a8acbf6b4840ab420eb6a63774bf4593b\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"c428ecd1a21f1457ca3beb4df71b8a079c410e41\",\n                            \"lessThan\": \"078deff25f8a849ecd1c3fe17b1e473b1cf44f28\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"c428ecd1a21f1457ca3beb4df71b8a079c410e41\",\n                            \"lessThan\": \"f88bb3606e4bd11ee035b682cddc2999e604609a\",\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/netlink/af_netlink.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"4.1\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"4.1\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.59\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.13\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/bdd55b8a8acbf6b4840ab420eb6a63774bf4593b","https://git.kernel.org/stable/c/078deff25f8a849ecd1c3fe17b1e473b1cf44f28","https://git.kernel.org/stable/c/f88bb3606e4bd11ee035b682cddc2999e604609a"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-99201","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-99201","identifiers":["CVE-2026-99201"]},"retained":false,"historicalAffected":[]}],"coverage":[]}