CVE-2026-43466

/* * PoC Concept: Trigger TX Error CQE to cause DMA FIFO desync. * Note: Requires Mellanox NIC and specific network conditions. */ // This is a conceptual representation of the bug. // Actual exploitation requires forcing a TX completion error. struct mlx5e_txqsq { u16 dma_fifo_cc; // Consumer counter u16 dma_fifo_pc; // Producer counter }; void vulnerable_recovery(struct mlx5e_txqsq *sq) { // Bug: Only resetting cc, not pc sq->dma_fifo_cc = 0; // sq->dma_fifo_pc remains unchanged -> Desync } // Result: Later unmaps use stale addresses.

{"cve": {"id": "CVE-2026-43466", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-08T15:16:59.543", "lastModified": "2026-05-11T08:16:15.767", "vulnStatus": "Received", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/mlx5e: Fix DMA FIFO desync on error CQE SQ recovery\n\nIn case of a TX error CQE, a recovery flow is triggered,\nmlx5e_reset_txqsq_cc_pc() resets dma_fifo_cc to 0 but not dma_fifo_pc,\ndesyncing the DMA FIFO producer and consumer.\n\nAfter recovery, the producer pushes new DMA entries at the old\ndma_fifo_pc, while the consumer reads from position 0.\nThis causes us to unmap stale DMA addresses from before the recovery.\n\nThe DMA FIFO is a purely software construct with no HW counterpart.\nAt the point of reset, all WQEs have been flushed so dma_fifo_cc is\nalready equal to dma_fifo_pc. There is no need to reset either counter,\nsimilar to how skb_fifo pc/cc are untouched.\n\nRemove the 'dma_fifo_cc = 0' reset.\n\nThis fixes the following WARNING:\n WARNING: CPU: 0 PID: 0 at drivers/iommu/dma-iommu.c:1240 iommu_dma_unmap_page+0x79/0x90\n Modules linked in: mlx5_vdpa vringh vdpa bonding mlx5_ib mlx5_vfio_pci ipip mlx5_fwctl tunnel4 mlx5_core ib_ipoib geneve ip6_gre ip_gre gre nf_tables ip6_tunnel rdma_ucm ib_uverbs ib_umad vfio_pci vfio_pci_core act_mirred act_skbedit act_vlan vhost_net vhost tap ip6table_mangle ip6table_nat ip6table_filter ip6_tables iptable_mangle cls_matchall nfnetlink_cttimeout act_gact cls_flower sch_ingress vhost_iotlb iptable_raw tunnel6 vfio_iommu_type1 vfio openvswitch nsh rpcsec_gss_krb5 auth_rpcgss oid_registry xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink iptable_nat nf_nat xt_addrtype br_netfilter overlay zram zsmalloc rpcrdma ib_iser libiscsi scsi_transport_iscsi rdma_cm iw_cm ib_cm ib_core fuse [last unloaded: nf_tables]\n CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.13.0-rc5_for_upstream_min_debug_2024_12_30_21_33 #1\n Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014\n RIP: 0010:iommu_dma_unmap_page+0x79/0x90\n Code: 2b 4d 3b 21 72 26 4d 3b 61 08 73 20 49 89 d8 44 89 f9 5b 4c 89 f2 4c 89 e6 48 89 ef 5d 41 5c 41 5d 41 5e 41 5f e9 c7 ae 9e ff <0f> 0b 5b 5d 41 5c 41 5d 41 5e 41 5f c3 66 2e 0f 1f 84 00 00 00 00\n Call Trace:\n <IRQ>\n ? __warn+0x7d/0x110\n ? iommu_dma_unmap_page+0x79/0x90\n ? report_bug+0x16d/0x180\n ? handle_bug+0x4f/0x90\n ? exc_invalid_op+0x14/0x70\n ? asm_exc_invalid_op+0x16/0x20\n ? iommu_dma_unmap_page+0x79/0x90\n ? iommu_dma_unmap_page+0x2e/0x90\n dma_unmap_page_attrs+0x10d/0x1b0\n mlx5e_tx_wi_dma_unmap+0xbe/0x120 [mlx5_core]\n mlx5e_poll_tx_cq+0x16d/0x690 [mlx5_core]\n mlx5e_napi_poll+0x8b/0xac0 [mlx5_core]\n __napi_poll+0x24/0x190\n net_rx_action+0x32a/0x3b0\n ? mlx5_eq_comp_int+0x7e/0x270 [mlx5_core]\n ? notifier_call_chain+0x35/0xa0\n handle_softirqs+0xc9/0x270\n irq_exit_rcu+0x71/0xd0\n common_interrupt+0x7f/0xa0\n </IRQ>\n <TASK>\n asm_common_interrupt+0x22/0x40"}], "metrics": {"cvssMetricV31": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H", "baseScore": 8.2, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 4.2}]}, "references": [{"url": "https://git.kernel.org/stable/c/1633111d69053512d099658d4a05fc736fab36b0", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/383b37c04a4827ba60b2bafc1a6cdfd995aed58f", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/6eb68ecc5acc3b319986566c595990b8a7265b23", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/6f41f7812bfa7f991b732a4b45c5c52fc4be3b4e", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/821f85d619f7f22cda7b9d7de89cf5eeb1d11544", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/829efcccfa8f69db5dc8332961295587d218cee6", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/9c5ee9b981ee050b73fdf3f4a2464d6f1a8e10a8", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/ce1b19dd0684eeb68a124c11085bd611260b36d9", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}]}}