{"id":"AZL-110933","summary":"CVE-2026-99053 affecting package kernel 6.6.157.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: hold a reference to nodes found by link name\n\ntipc_node_find_by_name() returns a node after dropping its RCU read lock\nwithout taking a reference.  The LINK_SET, LINK_GET and LINK_RESET_STATS\nhandlers then lock and access the node, racing with timer-driven cleanup of\na down peer.  Generic netlink serialization does not exclude the node\ntimer.\n\nThe following interleaving can leave a handler using a freed node:\n\n  CPU 0: find the node under RCU and release the node read lock\n  CPU 1: tipc_node_timeout() clears the links and unlinks the down node\n  CPU 1: drop the list and timer references, queuing tipc_node_free()\n  CPU 0: leave the RCU read-side critical section\n  CPU 1: complete the grace period and free the node\n  CPU 0: acquire the node lock through the stale pointer\n\nLINK_SET also uses the node's media address after releasing the node lock,\nwhen passing queued packets to tipc_bearer_xmit().\n\nKASAN on v7.3-rc5 reported:\n\n  BUG: KASAN: slab-use-after-free in _raw_read_lock_bh\n  Write of size 4 at addr ffff88807e06f008 by task poc/92\n  Call Trace:\n   _raw_read_lock_bh                 kernel/locking/spinlock.c:287\n   tipc_nl_node_set_link             net/tipc/node.c:2475\n   genl_family_rcv_msg_doit          net/netlink/genetlink.c:1114\n   genl_rcv_msg                      net/netlink/genetlink.c:1209\n   netlink_rcv_skb                   net/netlink/af_netlink.c:2575\n\n  Allocated by task 0:\n   tipc_node_create                  net/tipc/node.c:539\n   tipc_node_check_dest              net/tipc/node.c:1196\n   tipc_disc_rcv                     net/tipc/discover.c:252\n\n  Freed by task 92:\n   kfree                             mm/slub.c:6801\n   rcu_core                          kernel/rcu/tree.c:2919\n\n  Last potentially related work creation:\n   __call_rcu_common.constprop.0     kernel/rcu/tree.c:3181\n   tipc_node_timeout                 net/tipc/node.c:814\n\nAcquire a reference to the selected node with kref_get_unless_zero() before\nleaving RCU, returning NULL if the node has already been released.  Release\nthat reference on every caller exit after the last node access, including\ntransmission in LINK_SET.  Keep the existing link lookup order and locking\nso concurrent link removal still takes the existing error paths.","modified":"2026-10-25T05:30:37Z","published":"2026-10-23T13:17:28Z","upstream":["CVE-2026-99053"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-99053"}],"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-110933.json"}}],"schema_version":"1.9.0"}