GHSA-V4GX-744X-JR2M
Vulnerability from github – Published: 2026-06-24 09:30 – Updated: 2026-06-24 09:30In the Linux kernel, the following vulnerability has been resolved:
net/rds: fix NULL deref in rds_ib_send_cqe_handler() on masked atomic completion
rds_ib_xmit_atomic() always programs a masked atomic opcode (IB_WR_MASKED_ATOMIC_CMP_AND_SWP or IB_WR_MASKED_ATOMIC_FETCH_AND_ADD) for every RDS atomic cmsg. But the completion-side switch in rds_ib_send_unmap_op() only handles the non-masked opcodes, so a masked atomic completion falls through to default and returns rm == NULL while send->s_op is left set. rds_ib_send_cqe_handler() then dereferences the NULL rm via rm->m_final_op, oopsing in softirq context. An unprivileged AF_RDS sendmsg() of an atomic cmsg over an active RDS/IB connection triggers it; on hardware that natively accepts masked atomics (mlx4, mlx5) no extra setup is needed.
RDS/IB: rds_ib_send_unmap_op: unexpected opcode 0xd in WR! Oops: general protection fault [#1] SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000190-0x0000000000000197] RIP: rds_ib_send_cqe_handler+0x25c/0xb10 (net/rds/ib_send.c:282) Call Trace: rds_ib_send_cqe_handler (net/rds/ib_send.c:282) poll_scq (net/rds/ib_cm.c:274) rds_ib_tasklet_fn_send (net/rds/ib_cm.c:294) tasklet_action_common (kernel/softirq.c:943) handle_softirqs (kernel/softirq.c:573) run_ksoftirqd (kernel/softirq.c:479) Kernel panic - not syncing: Fatal exception in interrupt
Handle the masked atomic opcodes in the same case as the non-masked ones: they map to the same struct rds_message.atomic union member, so the existing container_of()/rds_ib_send_unmap_atomic() body is correct for them.
{
"affected": [],
"aliases": [
"CVE-2026-52939"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-06-24T08:16:24Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/rds: fix NULL deref in rds_ib_send_cqe_handler() on masked atomic completion\n\nrds_ib_xmit_atomic() always programs a masked atomic opcode\n(IB_WR_MASKED_ATOMIC_CMP_AND_SWP or IB_WR_MASKED_ATOMIC_FETCH_AND_ADD)\nfor every RDS atomic cmsg. But the completion-side switch in\nrds_ib_send_unmap_op() only handles the non-masked opcodes, so a masked\natomic completion falls through to default and returns rm == NULL while\nsend-\u003es_op is left set. rds_ib_send_cqe_handler() then dereferences the\nNULL rm via rm-\u003em_final_op, oopsing in softirq context. An unprivileged\nAF_RDS sendmsg() of an atomic cmsg over an active RDS/IB connection\ntriggers it; on hardware that natively accepts masked atomics (mlx4,\nmlx5) no extra setup is needed.\n\n RDS/IB: rds_ib_send_unmap_op: unexpected opcode 0xd in WR!\n Oops: general protection fault [#1] SMP KASAN\n KASAN: null-ptr-deref in range [0x0000000000000190-0x0000000000000197]\n RIP: rds_ib_send_cqe_handler+0x25c/0xb10 (net/rds/ib_send.c:282)\n Call Trace:\n \u003cIRQ\u003e\n rds_ib_send_cqe_handler (net/rds/ib_send.c:282)\n poll_scq (net/rds/ib_cm.c:274)\n rds_ib_tasklet_fn_send (net/rds/ib_cm.c:294)\n tasklet_action_common (kernel/softirq.c:943)\n handle_softirqs (kernel/softirq.c:573)\n run_ksoftirqd (kernel/softirq.c:479)\n \u003c/IRQ\u003e\n Kernel panic - not syncing: Fatal exception in interrupt\n\nHandle the masked atomic opcodes in the same case as the non-masked\nones: they map to the same struct rds_message.atomic union member, so\nthe existing container_of()/rds_ib_send_unmap_atomic() body is correct\nfor them.",
"id": "GHSA-v4gx-744x-jr2m",
"modified": "2026-06-24T09:30:48Z",
"published": "2026-06-24T09:30:48Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-52939"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0f22412a2f4fbbe0251c132abee045d15a90e5b6"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0f7baa82a24813cdad0b06a6f8f07e4824af5ed5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/34080db3e70ddf94c38512ad2331e3c3afca6cc1"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4dd262f875e87653df50b138de1390ab0628e6b7"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4fd34669558085bcb589aa2078a13b0ca79e360d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6e4615164d185a26badb2f376a2449f4d174a5f0"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a0148342badd8c9b2e46551766a27cb76c82e715"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/dcf458120add64c96a6ef5cf719340453f6e6abf"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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