{
  "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:  md: do overflow check for sb-\u003ebblog_shift in super_1_load()  In super_1_load(), sb-\u003ebblog_shift is an __u8 type value loaded from on- disk superblock. It is used for badblocks API badblocks_set() by the following sequence,   1930   rdev-\u003ebadblocks.shift = sb-\u003ebblog_shift;  1931   for (i = 0 ; i \u003c (sectors \u003c\u003c (9-3)) ; i++, bbp++) {  1932           u64 bb = le64_to_cpu(*bbp);  1933           int count = bb \u0026 (0x3ff);  1934           u64 sector = bb \u003e\u003e 10;  1935           sector \u003c\u003c= sb-\u003ebblog_shift;  1936           count \u003c\u003c= sb-\u003ebblog_shift;  1937           if (bb + 1 == 0)  1938                   break;  1939           if (!badblocks_set(\u0026rdev-\u003ebadblocks, sector, count, 1))  1940                   return -EINVAL;  1941   }  bb-\u003ebblog_shit is in range of 0-255, variable sector is 64bit width, for an invalid bb-\u003ebblog_shit, it is possible to make sector be overflowed by the following calculation,  1935           sector \u003c\u003c= sb-\u003ebblog_shift; Then in turn when call badblocks_set() at line 1939 with the invalid rdev-\u003ebadblocks.shift set at line 1930, may result an overflow inside _badblocks_clear() in block/badblocks.c.  Although there are many places to call badblocks APIs, the non-zero shift value is only used in super_1_load(), other places always use 0 as the shift value. Therefore it is unnecessary to do a general shift value overflow check inside badblock API, and just check here as the caller.  This may avoid unnecessary check, make the badblocks API code more simple and elegant.",
  "id": "DEBIAN-CVE-2026-89557",
  "modified": "2026-09-15T08:47:46.801231220Z",
  "published": "2026-09-11T20:19:39.403Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-89557"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "upstream": [
    "CVE-2026-89557"
  ]
}