zram: fix slot lock bit position on big-endian 64-bit

{
  "id": "12f53c95d9dbb9e32086fb8947b5b5e68851d5424e9a34bd94d61b4f04c0d66e",
  "url": "https://osv.dev/vulnerability/CVE-2026-90043",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "zram: fix slot lock bit position on big-endian 64-bit",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: zram: fix slot lock bit position on big-endian 64-bit The slot lock is a bit operation on the whole __lock word, which flags and ac_time alias as two u32s. On little-endian the lock bit lands in the position ZRAM_ENTRY_LOCK reserves in flags, so the aliasing works out. On 64-bit big-endian it lands in ac_time instead: with ZRAM_TRACK_ENTRY_ACTIME enabled, storing the access time from mark_slot_accessed() or slot_free() wipes out the held lock bit, letting another CPU take the same slot lock; an access time value with that bit set makes the slot look locked forever. Shift the lock bit into the flags half of the word on big-endian 64-bit.",
    "evidence": "osv:CVE-2026-90043",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "7.2.5",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-90043",
      "aliases": [
        "CVE-2026-90043"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "2e8ff2f51dde73a26b94aed2df4827177bd25e6e"
                },
                {
                  "fixed": "052b6b2d5fe97547bd2cdb73fa894f6cfea68b11"
                },
                {
                  "fixed": "a8b5875741d416703e19ad8eeac6fce8a12bd6e4"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90043.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "7.0.0"
                },
                {
                  "fixed": "7.2.5"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90043.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:50.164708051Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/052b6b2d5fe97547bd2cdb73fa894f6cfea68b11",
        "https://git.kernel.org/stable/c/a8b5875741d416703e19ad8eeac6fce8a12bd6e4",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90043.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-90043",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90043.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-90043",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 518612,
  "published_at": "2026-09-16T10:33:40.907+00:00"
}