FKIE_CVE-2026-90043

Vulnerability from fkie_nvd - Published: 2026-09-16 11:17 - Updated: 2026-10-19 09:18
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.
Impacted products
Vendor Product Version

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/block/zram/zram_drv.c",
            "drivers/block/zram/zram_drv.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "052b6b2d5fe97547bd2cdb73fa894f6cfea68b11",
              "status": "affected",
              "version": "2e8ff2f51dde73a26b94aed2df4827177bd25e6e",
              "versionType": "git"
            },
            {
              "lessThan": "a8b5875741d416703e19ad8eeac6fce8a12bd6e4",
              "status": "affected",
              "version": "2e8ff2f51dde73a26b94aed2df4827177bd25e6e",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/block/zram/zram_drv.c",
            "drivers/block/zram/zram_drv.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.0"
            },
            {
              "lessThan": "7.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nzram: fix slot lock bit position on big-endian 64-bit\n\nThe slot lock is a bit operation on the whole __lock word, which flags and\nac_time alias as two u32s.  On little-endian the lock bit lands in the\nposition ZRAM_ENTRY_LOCK reserves in flags, so the aliasing works out.  On\n64-bit big-endian it lands in ac_time instead: with\nZRAM_TRACK_ENTRY_ACTIME enabled, storing the access time from\nmark_slot_accessed() or slot_free() wipes out the held lock bit, letting\nanother CPU take the same slot lock; an access time value with that bit\nset makes the slot look locked forever.\n\nShift the lock bit into the flags half of the word on big-endian 64-bit."
    }
  ],
  "id": "CVE-2026-90043",
  "lastModified": "2026-10-19T09:18:52.590",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-16T11:17:17.557",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/052b6b2d5fe97547bd2cdb73fa894f6cfea68b11"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a8b5875741d416703e19ad8eeac6fce8a12bd6e4"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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