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

RDMA/rxe: Fix responder UAF on IB_QP_MAX_DEST_RD_ATOMIC modify_qp

rxe_qp_from_attr() handles IB_QP_MAX_DEST_RD_ATOMIC outside the
IB_QP_STATE path, so it holds no state_lock and runs while the responder
task rxe_receiver() (recv_task on rxe_wq) is live. A modify_qp() setting
only that attribute calls free_rd_atomic_resources() then
alloc_rd_atomic_resources(), swapping qp->resp.resources[] while
rxe_prepare_res()/find_resource() walk it; free_rd_atomic_resources()
also leaves the cached pointer qp->resp.res dangling. A local
unprivileged user can race the free/realloc into a use-after-free in
rxe_receiver() (local DoS).

Drain recv_task around the swap with rxe_disable_task()/rxe_enable_task(),
as rxe_qp_reset() already does when tearing this array down, re-enabling
only after alloc_rd_atomic_resources() succeeds so the responder never
resumes against a NULL qp->resp.resources on the ENOMEM path. Also clear
qp->resp.res in free_rd_atomic_resources(), like the rxe_resp.c
completion paths.

Reproduced under KASAN; the slab-use-after-free in rxe_receiver() is gone.
Published: 2026-09-04
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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History

Fri, 04 Sep 2026 19:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-416

Fri, 04 Sep 2026 16:00:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: RDMA/rxe: Fix responder UAF on IB_QP_MAX_DEST_RD_ATOMIC modify_qp rxe_qp_from_attr() handles IB_QP_MAX_DEST_RD_ATOMIC outside the IB_QP_STATE path, so it holds no state_lock and runs while the responder task rxe_receiver() (recv_task on rxe_wq) is live. A modify_qp() setting only that attribute calls free_rd_atomic_resources() then alloc_rd_atomic_resources(), swapping qp->resp.resources[] while rxe_prepare_res()/find_resource() walk it; free_rd_atomic_resources() also leaves the cached pointer qp->resp.res dangling. A local unprivileged user can race the free/realloc into a use-after-free in rxe_receiver() (local DoS). Drain recv_task around the swap with rxe_disable_task()/rxe_enable_task(), as rxe_qp_reset() already does when tearing this array down, re-enabling only after alloc_rd_atomic_resources() succeeds so the responder never resumes against a NULL qp->resp.resources on the ENOMEM path. Also clear qp->resp.res in free_rd_atomic_resources(), like the rxe_resp.c completion paths. Reproduced under KASAN; the slab-use-after-free in rxe_receiver() is gone.
Title RDMA/rxe: Fix responder UAF on IB_QP_MAX_DEST_RD_ATOMIC modify_qp
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-09-04T15:55:18.791Z

Reserved: 2026-08-26T14:34:25.798Z

Link: CVE-2026-80864

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-04T16:18:15.737

Modified: 2026-09-04T16:18:15.737

Link: CVE-2026-80864

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-04T19:15:07Z

Weaknesses