{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2026-23233",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-23233",
    "idYear": 2026,
    "status": "PUBLISHED",
    "publishedAt": "2026-03-04T14:36:38.076Z",
    "updatedAt": "2026-05-23T16:04:19.799Z",
    "importedAt": "2026-10-24T01:58:02.025Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "f2fs: fix to avoid mapping wrong physical block for swapfile",
      "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to avoid mapping wrong physical block for swapfile\n\nXiaolong Guo reported a f2fs bug in bugzilla [1]\n\n[1] https://bugzilla.kernel.org/show_bug.cgi?id=220951\n\nQuoted:\n\n\"When using stress-ng's swap stress test on F2FS filesystem with kernel 6.6+,\nthe system experiences data corruption leading to either:\n1 dm-verity corruption errors and device reboot\n2 F2FS node corruption errors and boot hangs\n\nThe issue occurs specifically when:\n1 Using F2FS filesystem (ext4 is unaffected)\n2 Swapfile size is less than F2FS section size (2MB)\n3 Swapfile has fragmented physical layout (multiple non-contiguous extents)\n4 Kernel version is 6.6+ (6.1 is unaffected)\n\nThe root cause is in check_swap_activate() function in fs/f2fs/data.c. When the\nfirst extent of a small swapfile (< 2MB) is not aligned to section boundaries,\nthe function incorrectly treats it as the last extent, failing to map\nsubsequent extents. This results in incorrect swap_extent creation where only\nthe first extent is mapped, causing subsequent swap writes to overwrite wrong\nphysical locations (other files' data).\n\nSteps to Reproduce\n1 Setup a device with F2FS-formatted userdata partition\n2 Compile stress-ng from https://github.com/ColinIanKing/stress-ng\n3 Run swap stress test: (Android devices)\nadb shell \"cd /data/stressng; ./stress-ng-64 --metrics-brief --timeout 60\n--swap 0\"\n\nLog:\n1 Ftrace shows in kernel 6.6, only first extent is mapped during second\nf2fs_map_blocks call in check_swap_activate():\nstress-ng-swap-8990: f2fs_map_blocks: ino=11002, file offset=0, start\nblkaddr=0x43143, len=0x1\n(Only 4KB mapped, not the full swapfile)\n2 in kernel 6.1, both extents are correctly mapped:\nstress-ng-swap-5966: f2fs_map_blocks: ino=28011, file offset=0, start\nblkaddr=0x13cd4, len=0x1\nstress-ng-swap-5966: f2fs_map_blocks: ino=28011, file offset=1, start\nblkaddr=0x60c84b, len=0xff\n\nThe problematic code is in check_swap_activate():\nif ((pblock - SM_I(sbi)->main_blkaddr) % blks_per_sec ||\n    nr_pblocks % blks_per_sec ||\n    !f2fs_valid_pinned_area(sbi, pblock)) {\n    bool last_extent = false;\n\n    not_aligned++;\n\n    nr_pblocks = roundup(nr_pblocks, blks_per_sec);\n    if (cur_lblock + nr_pblocks > sis->max)\n        nr_pblocks -= blks_per_sec;\n\n    /* this extent is last one */\n    if (!nr_pblocks) {\n        nr_pblocks = last_lblock - cur_lblock;\n        last_extent = true;\n    }\n\n    ret = f2fs_migrate_blocks(inode, cur_lblock, nr_pblocks);\n    if (ret) {\n        if (ret == -ENOENT)\n            ret = -EINVAL;\n        goto out;\n    }\n\n    if (!last_extent)\n        goto retry;\n}\n\nWhen the first extent is unaligned and roundup(nr_pblocks, blks_per_sec)\nexceeds sis->max, we subtract blks_per_sec resulting in nr_pblocks = 0. The\ncode then incorrectly assumes this is the last extent, sets nr_pblocks =\nlast_lblock - cur_lblock (entire swapfile), and performs migration. After\nmigration, it doesn't retry mapping, so subsequent extents are never processed.\n\"\n\nIn order to fix this issue, we need to lookup block mapping info after\nwe migrate all blocks in the tail of swapfile.",
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "40d76c393cca83938b11eb7ca8983aa3cd0ed69b",
              "status": "affected",
              "versionType": "git",
              "lessThan": "d4534a7f6c92baaf7e12a45fc6e37332cafafc33"
            },
            {
              "version": "9703d69d9d153bb230711d0d577454552aeb13d4",
              "status": "affected",
              "versionType": "git",
              "lessThan": "1ff415eef513bf12deb058fc50d57788c46c48e6"
            },
            {
              "version": "9703d69d9d153bb230711d0d577454552aeb13d4",
              "status": "affected",
              "versionType": "git",
              "lessThan": "fee27b69dde1a05908b350eea42937af2387c4fe"
            },
            {
              "version": "9703d69d9d153bb230711d0d577454552aeb13d4",
              "status": "affected",
              "versionType": "git",
              "lessThan": "607cb9d83838d2cd9f0406c2403ed61aadf0edff"
            },
            {
              "version": "9703d69d9d153bb230711d0d577454552aeb13d4",
              "status": "affected",
              "versionType": "git",
              "lessThan": "5c145c03188bc9ba1c29e0bc4d527a5978fc47f9"
            },
            {
              "version": "6.6.33",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "6.6.127"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "6.9",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "6.9"
            },
            {
              "version": "6.6.127",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "version": "6.12.74",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "version": "6.18.13",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "version": "6.19.3",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.19.*"
            },
            {
              "version": "7.0",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}