CVE-2026-89784 is a vulnerability in Linux Kernel
Published on September 16, 2026
SUNRPC: check rpc_sockaddr2uaddr() return value in rpcb_register_inet4/6
In 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.
Products Associated with CVE-2026-89784
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Affected Versions
Linux:- Version d77385f23830ee6c400569bac8b37e6eb3b7d360 and below 04441b792ec40eb66349b5fab34b6a2090b5b2dd is affected.
- Version d77385f23830ee6c400569bac8b37e6eb3b7d360 and below 5a51c49ddb37b883566874aecc66bc5a2e617a96 is affected.
- Version d77385f23830ee6c400569bac8b37e6eb3b7d360 and below 4a6095de8cb1858e05bdf70b3e7d6d7645c25041 is affected.
- Version d77385f23830ee6c400569bac8b37e6eb3b7d360 and below 12bf3e0182ccdaf3b412756a756d3944a7dacaa9 is affected.
- Version d77385f23830ee6c400569bac8b37e6eb3b7d360 and below 4e01022974355732e748ec8ebc97c558cb624ffe is affected.
- Version d77385f23830ee6c400569bac8b37e6eb3b7d360 and below cda4aacfb0bbf5c0f90fd0b42c72c749635d1368 is affected.
- Version d77385f23830ee6c400569bac8b37e6eb3b7d360 and below eb476289c12cc22c8766f8a84eeb7ab46c4e8fb6 is affected.
- Version d77385f23830ee6c400569bac8b37e6eb3b7d360 and below fd22370226a0d8109045d0831fd5aaadee921693 is affected.
- Version 3.2 is affected.
- Before 3.2 is unaffected.
- Version 5.10.270, <= 5.10.* is unaffected.
- Version 5.15.221, <= 5.15.* is unaffected.
- Version 6.1.188, <= 6.1.* is unaffected.
- Version 6.6.157, <= 6.6.* is unaffected.
- Version 6.12.110, <= 6.12.* is unaffected.
- Version 6.18.52, <= 6.18.* is unaffected.
- Version 7.2.6, <= 7.2.* is unaffected.
- Version 7.3-rc1, <= * is unaffected.