CVE-2026-80863

A flaw was found in the Linux kernel's RDMA/rxe component. A local user could exploit a memory corruption vulnerability in the free_rd_atomic_resources() function by updating the max_dest_rd_atomic value before the old array is properly freed, leading to an out-of-bounds write. This issue can cause a system crash, resulting in a denial of service (DoS).

An OOB write in RDMA/RXE free_rd_atomic_resources can occur because qp attr max_dest_rd_atomic is updated before the old rd atomic resources array is freed. The free path then uses the new larger bound while walking the old smaller allocation, which can write past the kmalloc object and corrupt slab memory. The issue is not directly network reachable because the triggering operation is a local uverbs control path rather than inbound RDMA traffic.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, prevent module rdma_rxe from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.