{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "d6ddfacd95c79d43465d4a85dffb1c9beca343a9"
            },
            {
              "fixed": "0b1a5d3647ce07c27a9fffefc11a8cbf7d7b25ce"
            },
            {
              "fixed": "87e2826ed2058747ddf014c082569a46bfadd96b"
            },
            {
              "fixed": "d3265c19b35d036bba327b36b5366bee76b0157c"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.19.0"
            },
            {
              "fixed": "6.12.111"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.53"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93830.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: stmmac: xgmac2: disable RBUE in default RX interrupt mask\n\nEnabling the RX Buffer Unavailable (RBUE) interrupt is counterproductive\nand can trigger a MAC interrupt storm under heavy RX pressure. When the\nDMA runs out of RX descriptors it fires RBUE continuously until software\nrefills the ring.\n\nHowever, RBUE is redundant: the normal RX completion interrupt (RIE)\nalready triggers NAPI, which processes completed descriptors and refills\nthe ring, causing the DMA to resume. The RBUE handler itself only sets\nhandle_rx - the same outcome as RIE.\n\nOn Agilex5 under heavy RX pressure, the MAC interrupt (which includes\nRBUE) was observed firing 1,821,811,555 times against only 2,618,627\nactual RX completions - a ~695x ratio - confirming the severity of the\nstorm.\n\nRBUE does not provide OOM recovery. If page_pool is exhausted,\nstmmac_rx_refill() cannot advance the DMA tail pointer, the DMA stays\nsuspended, and RBUE fires again on the next NAPI completion - a storm\nwith no forward progress. This patch trades that storm for a clean\nstall with the same RX outcome. Proper OOM recovery is a pre-existing\ngap outside the scope of this fix.\n\nNote: as a consequence of disabling RBUE, the rx_buf_unav_irq ethtool\ncounter will always read 0 on XGMAC2 devices. This behaviour is already\ninconsistent across DWMAC core versions.\n\nRemove RBUE from XGMAC_DMA_INT_DEFAULT_EN and XGMAC_DMA_INT_DEFAULT_RX\nto prevent the interrupt storm while keeping normal RX handling intact.",
  "id": "CVE-2026-93830",
  "modified": "2026-09-26T03:30:56.806370716Z",
  "published": "2026-09-24T16:03:12.818Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0b1a5d3647ce07c27a9fffefc11a8cbf7d7b25ce"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/87e2826ed2058747ddf014c082569a46bfadd96b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d3265c19b35d036bba327b36b5366bee76b0157c"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93830.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-93830"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "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": "net: stmmac: xgmac2: disable RBUE in default RX interrupt mask"
}