{
  "cveId": "CVE-2026-89722",
  "url": "https://patchblox.com/security/cve/CVE-2026-89722",
  "summary": "CVE-2026-89722 is fixed in linux on 1 platform by DEBIAN-CVE-2026-89722 (version 7.2.6-1), released September 23, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  PCI/sysfs: Fix out-of-bounds read in pci_write_l...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  PCI/sysfs: Fix out-of-bounds read in pci_write_legacy_io()  pci_write_legacy_io() loads 4 bytes from the kernfs write buffer regardless of how many bytes userspace wrote:    if (count != 1 \u0026\u0026 count != 2 \u0026\u0026 count != 4)           return -EINVAL;    return pci_legacy_write(bus, off, *(u32 *)buf, count);  kernfs_fop_write_iter() allocates the buffer with kmalloc(len \u002B 1), so a 1-byte write to the legacy_io sysfs file allocates 2 bytes and the unconditional u32 load reads up to 2 bytes past the end of the allocation, which KASAN reports as a slab-out-of-bounds read. Similarly, a 2-byte write overreads by 1 byte.  Thus, read only the number of bytes requested using get_unaligned_le16() and get_unaligned_le32() for the 2 and 4 byte cases, interpreting the buffer as little-endian to match the byte ordering of PCI I/O port space.  The PowerPC implementation previously compensated for the generic code\u0027s native-endian 32-bit load by shifting the value into place for the 1 and 2 byte cases.  The shifts were only correct on big-endian kernels.  On little-endian PowerPC (POWER8 and later), they extracted the wrong bytes, so a 1-byte write wrote an out-of-bounds byte instead of the requested value.  On big-endian, the native load also caused out_le16() and out_le32() to reverse the user\u0027s bytes on the wire for 2 and 4 byte writes.  The little-endian helpers resolve both issues, so the shifts are removed.  No changes are needed for the Alpha platform.  The legacy_io file is root-only and exists only on Alpha and PowerPC, the two architectures that define HAVE_PCI_LEGACY.",
  "published": "2026-09-11T20:20:01Z",
  "severity": "",
  "epss": 0.00206,
  "epssPercentile": 0.10779,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.6-1",
      "fix": "DEBIAN-CVE-2026-89722",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-89722",
      "released": "2026-09-23T19:19:02Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T01:18:40Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}