{ "affected": [ { "ranges": [ { "events": [ { "introduced": "c0c050c58d840994ba842ad1c338a98e7c12b764" }, { "fixed": "0f347e00d060dc0bf3b2d0ee041206e54848c233" }, { "fixed": "b3fd0177cf18a6ac98d41af80b4040010ea40f4d" }, { "fixed": "3a5d8465e73aff3c7d1ec38261dcaaa317367467" }, { "fixed": "cf8530a25ae92c4493e2f22981ecb46f0b66f4c8" }, { "fixed": "2956aca14dd2977cd08bd2ccafae3beb8b84b268" }, { "fixed": "fbd977e513971ccb4f0762a7f59eac500e474f89" }, { "fixed": "5213f65a9667d3dd85db2e6df8f2e0516290db34" }, { "fixed": "a51d233ccd4889aadb71dace863525cc2b00271e" } ], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "type": "GIT" } ] }, { "package": { "ecosystem": "Linux", "name": "Kernel" }, "ranges": [ { "events": [ { "introduced": "4.4.0" }, { "fixed": "5.10.273" } ], "type": "ECOSYSTEM" }, { "events": [ { "introduced": "5.11.0" }, { "fixed": "5.15.224" } ], "type": "ECOSYSTEM" }, { "events": [ { "introduced": "5.16.0" }, { "fixed": "6.1.191" } ], "type": "ECOSYSTEM" }, { "events": [ { "introduced": "6.2.0" }, { "fixed": "6.6.160" } ], "type": "ECOSYSTEM" }, { "events": [ { "introduced": "6.7.0" }, { "fixed": "6.12.113" } ], "type": "ECOSYSTEM" }, { "events": [ { "introduced": "6.13.0" }, { "fixed": "6.18.57" } ], "type": "ECOSYSTEM" }, { "events": [ { "introduced": "6.19.0" }, { "fixed": "7.2.11" } ], "type": "ECOSYSTEM" } ] } ], "database_specific": { "cna_assigner": "Linux", "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/99xxx/CVE-2026-99081.json" }, "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbnxt_en: fix DMA mapping length for padded small packets\n\nStefan Fleischmann reported Intel IOMMU DMA Read faults on BCM57412\nNetXtreme-E NICs when transmitting packets on VLAN/macvlan interfaces:\n\n DMAR: [DMA Read NO_PASID] Request device [18:00.0] fault addr 0xfc499000\n [fault reason 0x06] PTE Read access is not set\n bnxt_en 0000:18:00.0 eno1np0: Abandoning msg {0xb4 0x41a} len: 0 due to firmware status: 0x2000001\n ...\n NETDEV WATCHDOG: eno1np0 (bnxt_en): transmit queue 0 timed out\n\nThe fault address (0xfc499000) is on an exact 4KB page boundary,\npointing to a DMA read buffer overrun.\n\nIn bnxt_start_xmit(), packets smaller than BNXT_MIN_PKT_SIZE (52 bytes),\nsuch as 42-byte untagged ARP frames, are padded:\n\n if (length \u003c BNXT_MIN_PKT_SIZE) {\n pad = BNXT_MIN_PKT_SIZE - length;\n if (skb_pad(skb, pad))\n goto tx_kick_pending;\n length = BNXT_MIN_PKT_SIZE;\n }\n\n mapping = dma_map_single(\u0026pdev-\u003edev, skb-\u003edata, len, DMA_TO_DEVICE);\n ...\n dma_unmap_len_set(tx_buf, len, len);\n\nHowever, 'len' was initialized earlier to skb_headlen(skb) (e.g. 42 bytes)\nand is left unadjusted after padding. Consequently, dma_map_single() and\ndma_unmap_len_set() map and track only 42 bytes.\n\nLater, the hardware TX buffer descriptor is programmed with the padded length:\n\n txbd-\u003etx_bd_len_flags_type =\n cpu_to_le32(((len + pad) \u003c\u003c TX_BD_LEN_SHIFT) | flags |\n TX_BD_FLAGS_PACKET_END);\n\nThe NIC DMA engine is thus instructed to read 52 bytes from a region where\nonly 42 bytes were DMA-mapped. If skb-\u003edata ends near the boundary of a 4KB\npage (within 'pad' bytes of the next page), the hardware DMA read overruns\ninto the unmapped adjacent page, triggering an IOMMU fault.\n\nThis issue was exposed after commit 447cbe95ebb9 (\"vlan: fix skb_under_panic\nand races when toggling HW VLAN offload\") because reserving extra VLAN\nheadroom rounded LL_RESERVED_SPACE from 48 up to 64 bytes, shifting skb-\u003edata\noffsets and potentially causing small frames to land right against page\nboundaries.\n\nFix this by using skb_put_padto(skb, BNXT_MIN_PKT_SIZE) in\nbnxt_start_xmit(), before skb_shinfo(skb)-\u003enr_frags is sampled,\nbecause padding might linearize the skb.\nThis ensures skb-\u003elen and skb_headlen(skb) reflect the padded size so\nthat dma_map_single() maps the full buffer and the descriptor length is\nconsistent. This also removes the temporary 'pad' variable and masking logic.\n\nThe padding is done after the SW USO branch, otherwise\nbnxt_sw_udp_gso_xmit() would account the padding as UDP payload\nand send it in extra segments.\n\nNote that SW USO segments are still not padded: with IPv4, a segment\ncarrying less than 10 bytes of UDP payload (small gso_size, or a short\nlast segment) is sent as a frame shorter than BNXT_MIN_PKT_SIZE.\nThis is a separate issue, left for a followup patch.", "id": "CVE-2026-99081", "modified": "2026-11-01T02:31:02.842343053Z", "published": "2026-10-23T12:23:28.347Z", "references": [ { "type": "WEB", "url": "https://git.kernel.org/stable/c/0f347e00d060dc0bf3b2d0ee041206e54848c233" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/2956aca14dd2977cd08bd2ccafae3beb8b84b268" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/3a5d8465e73aff3c7d1ec38261dcaaa317367467" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/5213f65a9667d3dd85db2e6df8f2e0516290db34" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/a51d233ccd4889aadb71dace863525cc2b00271e" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/b3fd0177cf18a6ac98d41af80b4040010ea40f4d" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/cf8530a25ae92c4493e2f22981ecb46f0b66f4c8" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/fbd977e513971ccb4f0762a7f59eac500e474f89" }, { "type": "ADVISORY", "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/99xxx/CVE-2026-99081.json" }, { "type": "ADVISORY", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99081" }, { "type": "PACKAGE", "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git" } ], "schema_version": "1.9.2", "severity": [ { "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "type": "CVSS_V3" } ], "summary": "bnxt_en: fix DMA mapping length for padded small packets" }