{"id":"AZL-111362","summary":"CVE-2026-99201 affecting package kernel 6.6.157.1-1","details":"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.","modified":"2026-10-30T05:35:37Z","published":"2026-10-28T11:17:41Z","upstream":["CVE-2026-99201"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-99201"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.157.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-111362.json"}}],"schema_version":"1.9.2"}