CVE-2026-31425

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

rds: ib: reject FRMR registration before IB connection is established

rds_ib_get_mr() extracts the rds_ib_connection from conn->c_transport_data

and passes it to rds_ib_reg_frmr() for FRWR memory registration. On a

fresh outgoing connection, ic is allocated in rds_ib_conn_alloc() with

i_cm_id = NULL because the connection worker has not yet called

rds_ib_conn_path_connect() to create the rdma_cm_id. When sendmsg() with

RDS_CMSG_RDMA_MAP is called on such a connection, the sendmsg path parses

the control message before any connection establishment, allowing

rds_ib_post_reg_frmr() to dereference ic->i_cm_id->qp and crash the

kernel.

The existing guard in rds_ib_reg_frmr() only checks for !ic (added in

commit 9e630bcb7701), which does not catch this case since ic is allocated

early and is always non-NULL once the connection object exists.

KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]

RIP: 00

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References