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FKIE_CVE-2026-93048

Vulnerability from fkie_nvd - Published: 2026-09-17 17:17 - Updated: 2026-09-17 17:17
Severity
Summary
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->erasesize || !master->_erase) && !(mtd->flags & 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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/181c1bff940e7d3e34ca485d37e3cdbfe409203c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/398aca2f90122d5abbabff1079deaeb885fe9e40
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6aaab2ace3f7b55733d904e5549acf8405f03642
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/701c3ae7273e1adc20db5d97c42e0139b479f16b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a536eb57be58442b19398b2783071007ecfb1735
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b759d5bb6265419344ee9729fd0dc07ad85719d8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c645f6dd1af2ecc70fd3578e141f2f71fa9e4eff
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e204e5c49a012f99638633fdbd773e3c86260053
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/mtd/mtdpart.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "701c3ae7273e1adc20db5d97c42e0139b479f16b",
              "status": "affected",
              "version": "1a31368bf92ef2a7da3ba379672c405bd2751df9",
              "versionType": "git"
            },
            {
              "lessThan": "6aaab2ace3f7b55733d904e5549acf8405f03642",
              "status": "affected",
              "version": "1a31368bf92ef2a7da3ba379672c405bd2751df9",
              "versionType": "git"
            },
            {
              "lessThan": "181c1bff940e7d3e34ca485d37e3cdbfe409203c",
              "status": "affected",
              "version": "1a31368bf92ef2a7da3ba379672c405bd2751df9",
              "versionType": "git"
            },
            {
              "lessThan": "a536eb57be58442b19398b2783071007ecfb1735",
              "status": "affected",
              "version": "1a31368bf92ef2a7da3ba379672c405bd2751df9",
              "versionType": "git"
            },
            {
              "lessThan": "e204e5c49a012f99638633fdbd773e3c86260053",
              "status": "affected",
              "version": "1a31368bf92ef2a7da3ba379672c405bd2751df9",
              "versionType": "git"
            },
            {
              "lessThan": "398aca2f90122d5abbabff1079deaeb885fe9e40",
              "status": "affected",
              "version": "1a31368bf92ef2a7da3ba379672c405bd2751df9",
              "versionType": "git"
            },
            {
              "lessThan": "c645f6dd1af2ecc70fd3578e141f2f71fa9e4eff",
              "status": "affected",
              "version": "1a31368bf92ef2a7da3ba379672c405bd2751df9",
              "versionType": "git"
            },
            {
              "lessThan": "b759d5bb6265419344ee9729fd0dc07ad85719d8",
              "status": "affected",
              "version": "1a31368bf92ef2a7da3ba379672c405bd2751df9",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/mtd/mtdpart.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.2"
            },
            {
              "lessThan": "3.2",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "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\nmtd: part: reject MTDPART_OFS_RETAIN in mtd_add_partition()\n\nmtd_add_partition() does not reject the special offset value\nMTDPART_OFS_RETAIN (-3), which leads to a WARN_ON in\nadd_mtd_device() when called through the BLKPG ioctl on NAND\ndevices. The RETAIN value depends on cur_offset being the end of\nthe previous partition, but in the dynamic partition path\ncur_offset equals the offset argument itself, causing undefined\nbehavior.\n\nCommit 5daa7b21496a (\"mtd: prepare partition add and del functions\nfor ioctl requests\") introduced mtd_add_partition() and correctly\nrejected MTDPART_OFS_APPEND (-1) and MTDPART_OFS_NXTBLK (-2),\nsince those special offsets rely on cur_offset tracking the\nprevious partition\u0027s end. However, commit 1a31368bf92e (\"mtd: add a flags\nfor partitions which should just leave smth. after them\")\nlater added MTDPART_OFS_RETAIN (-3) for the static\npartition table path without updating mtd_add_partition() to\nalso reject this value.\n\nWith offset=-3 passed via BLKPG, the RETAIN size calculation in\nallocate_partition() underflows (parent_size - 0xFFFFFFFFFFFFFFFD\n= parent_size + 3). If the underflow result does not appear to\nleave enough space, allocate_partition() jumps to out_register via\ngoto, skipping erasesize initialization. This results in\nerasesize=0, which triggers:\n\nWARN_ON((!mtd-\u003eerasesize || !master-\u003e_erase) \u0026\u0026\n\t\t!(mtd-\u003eflags \u0026 MTD_NO_ERASE))\n\nin add_mtd_device(). If the underflow result appears to leave\nenough space, a bogus partition size is calculated, but the\n\"out of reach\" sanity check catches the invalid offset and\ncreates a disabled empty partition (offset=0, size=0) instead\nof returning an error.\n\nFix this by adding MTDPART_OFS_RETAIN to the rejection list in\nmtd_add_partition(), consistent with the existing handling of\nAPPEND and NXTBLK."
    }
  ],
  "id": "CVE-2026-93048",
  "lastModified": "2026-09-17T17:17:58.080",
  "metrics": {},
  "published": "2026-09-17T17:17:58.080",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/181c1bff940e7d3e34ca485d37e3cdbfe409203c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/398aca2f90122d5abbabff1079deaeb885fe9e40"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6aaab2ace3f7b55733d904e5549acf8405f03642"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/701c3ae7273e1adc20db5d97c42e0139b479f16b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a536eb57be58442b19398b2783071007ecfb1735"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b759d5bb6265419344ee9729fd0dc07ad85719d8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c645f6dd1af2ecc70fd3578e141f2f71fa9e4eff"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e204e5c49a012f99638633fdbd773e3c86260053"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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