{
  "cveId": "CVE-2026-93830",
  "url": "https://patchblox.com/security/cve/CVE-2026-93830",
  "summary": "CVE-2026-93830 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-93830, released September 24, 2026. It is not reported as exploited. Patch Radar priority: High.",
  "title": "net: stmmac: xgmac2: disable RBUE in default RX interrupt mask",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  net: stmmac: xgmac2: disable RBUE in default RX interrupt mask  Enabling the RX Buffer Unavailable (RBUE) interrupt is counterproductive and can trigger a MAC interrupt storm under heavy RX pressure. When the DMA runs out of RX descriptors it fires RBUE continuously until software refills the ring.  However, RBUE is redundant: the normal RX completion interrupt (RIE) already triggers NAPI, which processes completed descriptors and refills the ring, causing the DMA to resume. The RBUE handler itself only sets handle_rx - the same outcome as RIE.  On Agilex5 under heavy RX pressure, the MAC interrupt (which includes RBUE) was observed firing 1,821,811,555 times against only 2,618,627 actual RX completions - a ~695x ratio - confirming the severity of the storm.  RBUE does not provide OOM recovery. If page_pool is exhausted, stmmac_rx_refill() cannot advance the DMA tail pointer, the DMA stays suspended, and RBUE fires again on the next NAPI completion - a storm with no forward progress. This patch trades that storm for a clean stall with the same RX outcome. Proper OOM recovery is a pre-existing gap outside the scope of this fix.  Note: as a consequence of disabling RBUE, the rx_buf_unav_irq ethtool counter will always read 0 on XGMAC2 devices. This behaviour is already inconsistent across DWMAC core versions.  Remove RBUE from XGMAC_DMA_INT_DEFAULT_EN and XGMAC_DMA_INT_DEFAULT_RX to prevent the interrupt storm while keeping normal RX handling intact.",
  "published": "2026-09-24T17:17:16Z",
  "severity": "Moderate",
  "cvss": 7.5,
  "cvssVector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
  "epss": 0.0049,
  "epssPercentile": 0.42404,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-93830",
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "6.1.190-1",
      "fix": "DEBIAN-CVE-2026-93830",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-93830",
      "released": "2026-09-24T19:30:44Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.12.111-1",
      "fix": "DEBIAN-CVE-2026-93830",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-93830",
      "released": "2026-09-24T19:30:44Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.6-1",
      "fix": "DEBIAN-CVE-2026-93830",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-93830",
      "released": "2026-09-24T19:30:44Z"
    },
    {
      "platform": "linux",
      "product": "linux-6.12",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "6.12.111-1~deb12u1",
      "fix": "DEBIAN-CVE-2026-93830",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-93830",
      "released": "2026-09-24T19:30:44Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T07:25:28Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}