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FKIE_CVE-2026-89718

Vulnerability from fkie_nvd - Published: 2026-09-11 20:19 - Updated: 2026-09-11 20:19
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: zram: fix out-of-bounds access in writeback_store() Patch series "zram: fix stale scan bounds after reinitialization". Both writeback_store() and read_block_state() derive their table scan bounds from zram->disksize before acquiring dev_lock. If the device is reset and reinitialized with a smaller disksize between that read and lock acquisition, the bound can describe the old table while the scan operates on the new one. This can lead to out-of-bounds slot accesses. Move both bound calculations under dev_lock so each bound remains consistent with the table throughout its scan. Keep the fixes separate because the affected interfaces originate from different commits and can be backported independently. This patch (of 2): writeback_store() calculates the table scan bounds before taking dev_lock. A reset followed by reconfiguration with a smaller disksize can therefore replace zram->table while writeback_store() is waiting for the lock. Once it acquires the lock, it sees an initialized device but scans the new table using the old upper bound, resulting in an out-of-bounds access. Calculate the number of pages while holding dev_lock so the scan bound matches the table protected by the lock.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/07a82a66f8c1894d92e51d97542c32ebf2c51b09
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/894913e2d35c46ff19a77530907771ae57862b96
Impacted products
Vendor Product Version
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{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/block/zram/zram_drv.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "07a82a66f8c1894d92e51d97542c32ebf2c51b09",
              "status": "affected",
              "version": "a939888ec38bf1f33e4a903056677e92a4844244",
              "versionType": "git"
            },
            {
              "lessThan": "894913e2d35c46ff19a77530907771ae57862b96",
              "status": "affected",
              "version": "a939888ec38bf1f33e4a903056677e92a4844244",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/block/zram/zram_drv.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.0"
            },
            {
              "lessThan": "5.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "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 out-of-bounds access in writeback_store()\n\nPatch series \"zram: fix stale scan bounds after reinitialization\".\n\nBoth writeback_store() and read_block_state() derive their table scan\nbounds from zram-\u003edisksize before acquiring dev_lock.  If the device is\nreset and reinitialized with a smaller disksize between that read and lock\nacquisition, the bound can describe the old table while the scan operates\non the new one.  This can lead to out-of-bounds slot accesses.\n\nMove both bound calculations under dev_lock so each bound remains\nconsistent with the table throughout its scan.  Keep the fixes separate\nbecause the affected interfaces originate from different commits and can\nbe backported independently.\n\n\nThis patch (of 2):\n\nwriteback_store() calculates the table scan bounds before taking dev_lock.\nA reset followed by reconfiguration with a smaller disksize can therefore\nreplace zram-\u003etable while writeback_store() is waiting for the lock.  Once\nit acquires the lock, it sees an initialized device but scans the new\ntable using the old upper bound, resulting in an out-of-bounds access.\n\nCalculate the number of pages while holding dev_lock so the scan bound\nmatches the table protected by the lock."
    }
  ],
  "id": "CVE-2026-89718",
  "lastModified": "2026-09-11T20:19:59.377",
  "metrics": {},
  "published": "2026-09-11T20:19:59.377",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/07a82a66f8c1894d92e51d97542c32ebf2c51b09"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/894913e2d35c46ff19a77530907771ae57862b96"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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