GHSA-8JPC-3W39-9JVG
Vulnerability from github – Published: 2026-09-16 09:30 – Updated: 2026-09-16 09:30In the Linux kernel, the following vulnerability has been resolved:
SUNRPC: check rpc_sockaddr2uaddr() return value in rpcb_register_inet4/6
rpcb_register_inet4() and rpcb_register_inet6() store the result of rpc_sockaddr2uaddr() into map->r_addr without checking it for NULL. rpc_sockaddr2uaddr() returns NULL when its final kstrdup() fails, and the unchecked NULL is then carried into the synchronous RPCBPROC_SET encode path: rpcb_register_call() -> rpc_call_sync() -> rpcb_enc_getaddr() -> encode_rpcb_string(), whose first statement is strlen(string), dereferencing NULL and oopsing the kernel.
The crash reproduces under failslab on v6.12; with KASAN the NULL dereference surfaces as a fault on the shadow of address zero:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000 [#1] PREEMPT SMP KASAN RIP: 0010:strlen (lib/string.c:409) Call Trace: encode_rpcb_string (net/sunrpc/rpcb_clnt.c:890) rpcb_enc_getaddr (net/sunrpc/rpcb_clnt.c:910) rpcauth_wrap_req_encode (net/sunrpc/auth.c:745) call_encode (net/sunrpc/clnt.c:1966) __rpc_execute (net/sunrpc/sched.c:952) rpc_run_task (net/sunrpc/clnt.c:1243) rpc_call_sync (net/sunrpc/clnt.c:1272) rpcb_v4_register (net/sunrpc/rpcb_clnt.c:500) svc_generic_rpcbind_set nfsd_rpcbind_set svc_register svc_setup_socket svc_addsock write_ports nfsctl_transaction_write vfs_write
The crash is reachable when an in-kernel RPC service (nfsd, lockd, nfs-callback) registers with the local rpcbind under enough memory pressure for the small GFP_KERNEL kstrdup() in rpc_sockaddr2uaddr() to fail. The asynchronous getport path already handles this exact failure mode by returning -ENOMEM; only the two register helpers omit the check.
Mirror that handling: bail out with -ENOMEM when rpc_sockaddr2uaddr() returns NULL, before the address is fed into the encoder.
{
"affected": [],
"aliases": [
"CVE-2026-89784"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-16T09:17:09Z",
"severity": null
},
"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.",
"id": "GHSA-8jpc-3w39-9jvg",
"modified": "2026-09-16T09:30:30Z",
"published": "2026-09-16T09:30:30Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89784"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/04441b792ec40eb66349b5fab34b6a2090b5b2dd"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/12bf3e0182ccdaf3b412756a756d3944a7dacaa9"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4a6095de8cb1858e05bdf70b3e7d6d7645c25041"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4e01022974355732e748ec8ebc97c558cb624ffe"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5a51c49ddb37b883566874aecc66bc5a2e617a96"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/cda4aacfb0bbf5c0f90fd0b42c72c749635d1368"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/eb476289c12cc22c8766f8a84eeb7ab46c4e8fb6"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fd22370226a0d8109045d0831fd5aaadee921693"
}
],
"schema_version": "1.4.0",
"severity": []
}
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