{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:12",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:13",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:  mtd: part: reject MTDPART_OFS_RETAIN in mtd_add_partition()  mtd_add_partition() does not reject the special offset value MTDPART_OFS_RETAIN (-3), which leads to a WARN_ON in add_mtd_device() when called through the BLKPG ioctl on NAND devices. The RETAIN value depends on cur_offset being the end of the previous partition, but in the dynamic partition path cur_offset equals the offset argument itself, causing undefined behavior.  Commit 5daa7b21496a (\"mtd: prepare partition add and del functions for ioctl requests\") introduced mtd_add_partition() and correctly rejected MTDPART_OFS_APPEND (-1) and MTDPART_OFS_NXTBLK (-2), since those special offsets rely on cur_offset tracking the previous partition's end. However, commit 1a31368bf92e (\"mtd: add a flags for partitions which should just leave smth. after them\") later added MTDPART_OFS_RETAIN (-3) for the static partition table path without updating mtd_add_partition() to also reject this value.  With offset=-3 passed via BLKPG, the RETAIN size calculation in allocate_partition() underflows (parent_size - 0xFFFFFFFFFFFFFFFD = parent_size + 3). If the underflow result does not appear to leave enough space, allocate_partition() jumps to out_register via goto, skipping erasesize initialization. This results in erasesize=0, which triggers:  WARN_ON((!mtd-\u003eerasesize || !master-\u003e_erase) \u0026\u0026 \t\t!(mtd-\u003eflags \u0026 MTD_NO_ERASE))  in add_mtd_device(). If the underflow result appears to leave enough space, a bogus partition size is calculated, but the \"out of reach\" sanity check catches the invalid offset and creates a disabled empty partition (offset=0, size=0) instead of returning an error.  Fix this by adding MTDPART_OFS_RETAIN to the rejection list in mtd_add_partition(), consistent with the existing handling of APPEND and NXTBLK.",
  "id": "DEBIAN-CVE-2026-93048",
  "modified": "2026-09-18T04:47:25.162889088Z",
  "published": "2026-09-17T17:17:58.080Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-93048"
    }
  ],
  "upstream": [
    "CVE-2026-93048"
  ]
}