{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "2271048d1b3b0aabf83d25b29c20646dcabedc05"
            },
            {
              "fixed": "7c9f0ccf9f04142458d2ac3d39414f4acae242f0"
            },
            {
              "fixed": "24c3fa71f9947b0e1f3b954db1b769b44140192e"
            },
            {
              "fixed": "14057268e79654c3e8ea2c9b5204cb9644b2964d"
            },
            {
              "fixed": "dbcb8635b1eb7603818591cf745c7b1d714f7ac6"
            },
            {
              "fixed": "cfada73fabe2ccc06ec77fe2ceaa088689213326"
            },
            {
              "fixed": "ec5e96aee75d27779b9a860307679f13f33adb0c"
            },
            {
              "fixed": "3a63a11897c7ba32d1be7a3fdbc48a8b01cf4992"
            },
            {
              "fixed": "c37e0a4b79a6bbb96ce5ffe279d7c001e20529e0"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.6.34"
            },
            {
              "fixed": "5.10.261"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.212"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.178"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.145"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.97"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.40"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80876.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Fix event length with forced 8-byte alignment\n\nWhen RB_FORCE_8BYTE_ALIGNMENT is true, rb_calculate_event_length()\nreserves the space of event-\u003earray[0] for placing the data length and\nrb_update_event() stores the data length in event-\u003earray[0]\naccordingly. As a result the whole event length will add extra 4 bytes\nfor sizeof(event.array[0]) unconditionally.\n\nBut ring_buffer_event_length() only subtracts the\nsizeof(event-\u003earray[0]) for events larger than RB_MAX_SMALL_DATA +\nsizeof(event-\u003earray[0]). As a result, small events on architectures\nwith RB_FORCE_8BYTE_ALIGNMENT=true report a data length that is 4\nbytes larger than expected.\n\nTo fix it, add the RB_FORCE_8BYTE_ALIGNMENT as a condition to subtract\nthe size of that length field whenever RB_FORCE_8BYTE_ALIGNMENT is\ntrue.\n\nThis issue is observed in a riscv64 kernel with\nCONFIG_HAVE_64BIT_ALIGNED_ACCESS set to y, when we run ftrace selftest\ntrace_marker_raw.tc, we get the weird log: for cases where the id is\n1..100, the number of data field is 8*N, but once id exceeds 100, the\nnumber of data field becomes 8*N+4:\n # 1 buf: 58 00 00 00 80 5e d1 63 (number of data field is 8*1)\n ...\n # a buf: 58 ...                  (number of data field is 8*2)\n ...\n # 64 buf: 58 ...                 (number of data field is 8*13)\n # 65 buf: 58 ...                 (number of data field is 8*13+4)\n\nAfter applying this change, the number of data field keeps being 8*N+4\nconsistently.",
  "id": "CVE-2026-80876",
  "modified": "2026-09-06T03:30:18.255808699Z",
  "published": "2026-09-04T16:48:50.082Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/14057268e79654c3e8ea2c9b5204cb9644b2964d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/24c3fa71f9947b0e1f3b954db1b769b44140192e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3a63a11897c7ba32d1be7a3fdbc48a8b01cf4992"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7c9f0ccf9f04142458d2ac3d39414f4acae242f0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c37e0a4b79a6bbb96ce5ffe279d7c001e20529e0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cfada73fabe2ccc06ec77fe2ceaa088689213326"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dbcb8635b1eb7603818591cf745c7b1d714f7ac6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ec5e96aee75d27779b9a860307679f13f33adb0c"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80876.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80876"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "ring-buffer: Fix event length with forced 8-byte alignment"
}