{"id":"AZL-101508","summary":"CVE-2026-89784 affecting package kernel 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: check rpc_sockaddr2uaddr() return value in rpcb_register_inet4/6\n\nrpcb_register_inet4() and rpcb_register_inet6() store the result of\nrpc_sockaddr2uaddr() into map-\u003er_addr without checking it for NULL.\nrpc_sockaddr2uaddr() returns NULL when its final kstrdup() fails, and\nthe unchecked NULL is then carried into the synchronous RPCBPROC_SET\nencode path: rpcb_register_call() -\u003e rpc_call_sync() -\u003e\nrpcb_enc_getaddr() -\u003e encode_rpcb_string(), whose first statement is\nstrlen(string), dereferencing NULL and oopsing the kernel.\n\nThe crash reproduces under failslab on v6.12; with KASAN the NULL\ndereference surfaces as a fault on the shadow of address zero:\n\n Oops: general protection fault, probably for non-canonical address\n       0xdffffc0000000000 [#1] PREEMPT SMP KASAN\n RIP: 0010:strlen (lib/string.c:409)\n Call Trace:\n  encode_rpcb_string (net/sunrpc/rpcb_clnt.c:890)\n  rpcb_enc_getaddr (net/sunrpc/rpcb_clnt.c:910)\n  rpcauth_wrap_req_encode (net/sunrpc/auth.c:745)\n  call_encode (net/sunrpc/clnt.c:1966)\n  __rpc_execute (net/sunrpc/sched.c:952)\n  rpc_run_task (net/sunrpc/clnt.c:1243)\n  rpc_call_sync (net/sunrpc/clnt.c:1272)\n  rpcb_v4_register (net/sunrpc/rpcb_clnt.c:500)\n  svc_generic_rpcbind_set\n  nfsd_rpcbind_set\n  svc_register\n  svc_setup_socket\n  svc_addsock\n  write_ports\n  nfsctl_transaction_write\n  vfs_write\n\nThe crash is reachable when an in-kernel RPC service (nfsd, lockd,\nnfs-callback) registers with the local rpcbind under enough memory\npressure for the small GFP_KERNEL kstrdup() in rpc_sockaddr2uaddr() to\nfail. The asynchronous getport path already handles this exact failure\nmode by returning -ENOMEM; only the two register helpers omit the check.\n\nMirror that handling: bail out with -ENOMEM when rpc_sockaddr2uaddr()\nreturns NULL, before the address is fed into the encoder.","modified":"2026-09-17T14:15:57.590737468Z","published":"2026-09-16T09:17:09Z","upstream":["CVE-2026-89784"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89784"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-101508.json"}}],"schema_version":"1.9.0"}