CVE-2025-38218 (GCVE-0-2025-38218)
Vulnerability from cvelistv5
Published
2025-07-04 13:37
Modified
2026-08-05 12:00
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to do sanity check on sit_bitmap_size w/ below testcase, resize will generate a corrupted image which contains inconsistent metadata, so when mounting such image, it will trigger kernel panic: touch img truncate -s $((512*1024*1024*1024)) img mkfs.f2fs -f img $((256*1024*1024)) resize.f2fs -s -i img -t $((1024*1024*1024)) mount img /mnt/f2fs ------------[ cut here ]------------ kernel BUG at fs/f2fs/segment.h:863! Oops: invalid opcode: 0000 [#1] SMP PTI CPU: 11 UID: 0 PID: 3922 Comm: mount Not tainted 6.15.0-rc1+ #191 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:f2fs_ra_meta_pages+0x47c/0x490 Call Trace: f2fs_build_segment_manager+0x11c3/0x2600 f2fs_fill_super+0xe97/0x2840 mount_bdev+0xf4/0x140 legacy_get_tree+0x2b/0x50 vfs_get_tree+0x29/0xd0 path_mount+0x487/0xaf0 __x64_sys_mount+0x116/0x150 do_syscall_64+0x82/0x190 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7fdbfde1bcfe The reaseon is: sit_i->bitmap_size is 192, so size of sit bitmap is 192*8=1536, at maximum there are 1536 sit blocks, however MAIN_SEGS is 261893, so that sit_blk_cnt is 4762, build_sit_entries() -> current_sit_addr() tries to access out-of-boundary in sit_bitmap at offset from [1536, 4762), once sit_bitmap and sit_bitmap_mirror is not the same, it will trigger f2fs_bug_on(). Let's add sanity check in f2fs_sanity_check_ckpt() to avoid panic.
References
Impacted products
Vendor Product Version
Linux Linux Version: 98e4da8ca301e062d79ae168c67e56f3c3de3ce4
Version: 98e4da8ca301e062d79ae168c67e56f3c3de3ce4
Version: 98e4da8ca301e062d79ae168c67e56f3c3de3ce4
Version: 98e4da8ca301e062d79ae168c67e56f3c3de3ce4
Version: 98e4da8ca301e062d79ae168c67e56f3c3de3ce4
Version: 98e4da8ca301e062d79ae168c67e56f3c3de3ce4
Version: 98e4da8ca301e062d79ae168c67e56f3c3de3ce4
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2025-11-03T17:35:36.324Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"
          },
          {
            "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/f2fs/super.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "82f51bff393e4c12cf4de553120ca831cfa4ef19",
              "status": "affected",
              "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4",
              "versionType": "git"
            },
            {
              "lessThan": "38ef48a8afef8df646b6f6ae7abb872f18b533c1",
              "status": "affected",
              "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4",
              "versionType": "git"
            },
            {
              "lessThan": "ad862f71016ba38039df1c96ed55c0a4314cc183",
              "status": "affected",
              "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4",
              "versionType": "git"
            },
            {
              "lessThan": "79ef8a6c4ec53d327580fd7d2b522cf4f1d05b0c",
              "status": "affected",
              "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4",
              "versionType": "git"
            },
            {
              "lessThan": "ee1b421c469876544e297ec1090574bd76100247",
              "status": "affected",
              "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4",
              "versionType": "git"
            },
            {
              "lessThan": "3e5ac62a56a24f4d88ce8ffd7bc452428b235868",
              "status": "affected",
              "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4",
              "versionType": "git"
            },
            {
              "lessThan": "5db0d252c64e91ba1929c70112352e85dc5751e7",
              "status": "affected",
              "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/f2fs/super.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.8"
            },
            {
              "lessThan": "3.8",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.239",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.186",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.142",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.95",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.35",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.15.*",
              "status": "unaffected",
              "version": "6.15.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.16",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.239",
                  "versionStartIncluding": "3.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.186",
                  "versionStartIncluding": "3.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.142",
                  "versionStartIncluding": "3.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.95",
                  "versionStartIncluding": "3.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.35",
                  "versionStartIncluding": "3.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.15.4",
                  "versionStartIncluding": "3.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.16",
                  "versionStartIncluding": "3.8",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to do sanity check on sit_bitmap_size\n\nw/ below testcase, resize will generate a corrupted image which\ncontains inconsistent metadata, so when mounting such image, it\nwill trigger kernel panic:\n\ntouch img\ntruncate -s $((512*1024*1024*1024)) img\nmkfs.f2fs -f img $((256*1024*1024))\nresize.f2fs -s -i img -t $((1024*1024*1024))\nmount img /mnt/f2fs\n\n------------[ cut here ]------------\nkernel BUG at fs/f2fs/segment.h:863!\nOops: invalid opcode: 0000 [#1] SMP PTI\nCPU: 11 UID: 0 PID: 3922 Comm: mount Not tainted 6.15.0-rc1+ #191 PREEMPT(voluntary)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\nRIP: 0010:f2fs_ra_meta_pages+0x47c/0x490\n\nCall Trace:\n f2fs_build_segment_manager+0x11c3/0x2600\n f2fs_fill_super+0xe97/0x2840\n mount_bdev+0xf4/0x140\n legacy_get_tree+0x2b/0x50\n vfs_get_tree+0x29/0xd0\n path_mount+0x487/0xaf0\n __x64_sys_mount+0x116/0x150\n do_syscall_64+0x82/0x190\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\nRIP: 0033:0x7fdbfde1bcfe\n\nThe reaseon is:\n\nsit_i-\u003ebitmap_size is 192, so size of sit bitmap is 192*8=1536, at maximum\nthere are 1536 sit blocks, however MAIN_SEGS is 261893, so that sit_blk_cnt\nis 4762, build_sit_entries() -\u003e current_sit_addr() tries to access\nout-of-boundary in sit_bitmap at offset from [1536, 4762), once sit_bitmap\nand sit_bitmap_mirror is not the same, it will trigger f2fs_bug_on().\n\nLet\u0027s add sanity check in f2fs_sanity_check_ckpt() to avoid panic."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerability is reached through the local `mount(2)` path (`f2fs_fill_super` \u2192 `f2fs_build_segment_manager` \u2192 `build_sit_entries`) when a crafted f2fs image is attached, and the subsequent OOB write is reached via ordinary local file writes triggering a checkpoint. No network exposure exists.\nAC:L - The attacker fully controls the on-disk `sit_ver_bitmap_bytesize` and `segment_count_main` fields, so the out-of-bounds offset is deterministic and reproducible on every mount \u2014 the PoC is four shell commands with no race, timing, or memory-layout luck required to trigger it.\nPR:L - An unprivileged local user can get the crafted image mounted through removable-media auto-mount paths that are ubiquitous for f2fs \u2014 Android vold mounting SD/adoptable storage and udisks2 on desktops \u2014 without holding real `CAP_SYS_ADMIN` in the init namespace.\nUI:N - The attacker supplies and mounts the image themselves via auto-mount or delegated mount rights; no action by a separate victim user is needed, and the follow-on OOB write in `f2fs_flush_sit_entries()` fires from the attacker\u0027s own writes.\nS:U - The out-of-bounds access corrupts kernel slab memory within the same kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - `current_sit_addr()` performs a heap out-of-bounds read of the `kmemdup`\u0027d `sit_bitmap` at an attacker-chosen offset extending thousands of bits (up to ~19 KB) past the slab object, and the values read steer computed metadata block addresses, providing an oracle over adjacent kernel heap contents.\nI:H - `f2fs_flush_sit_entries()` \u2192 `get_next_sit_folio()` \u2192 `set_to_next_sit()` \u2192 `f2fs_change_bit()` performs an out-of-bounds bit flip at the same attacker-chosen offset, corrupting adjacent slab objects \u2014 a heap-corruption primitive suitable for control-flow hijacking with standard grooming.\nA:H - The reported impact is an immediate kernel panic \u2014 `BUG()` via `f2fs_bug_on()` at `fs/f2fs/segment.h:863` inside `f2fs_ra_meta_pages()` during mount \u2014 and the far out-of-bounds accesses can also fault on unmapped memory."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:00:26.742Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/82f51bff393e4c12cf4de553120ca831cfa4ef19"
        },
        {
          "url": "https://git.kernel.org/stable/c/38ef48a8afef8df646b6f6ae7abb872f18b533c1"
        },
        {
          "url": "https://git.kernel.org/stable/c/ad862f71016ba38039df1c96ed55c0a4314cc183"
        },
        {
          "url": "https://git.kernel.org/stable/c/79ef8a6c4ec53d327580fd7d2b522cf4f1d05b0c"
        },
        {
          "url": "https://git.kernel.org/stable/c/ee1b421c469876544e297ec1090574bd76100247"
        },
        {
          "url": "https://git.kernel.org/stable/c/3e5ac62a56a24f4d88ce8ffd7bc452428b235868"
        },
        {
          "url": "https://git.kernel.org/stable/c/5db0d252c64e91ba1929c70112352e85dc5751e7"
        }
      ],
      "title": "f2fs: fix to do sanity check on sit_bitmap_size",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-38218",
    "datePublished": "2025-07-04T13:37:35.157Z",
    "dateReserved": "2025-04-16T04:51:23.995Z",
    "dateUpdated": "2026-08-05T12:00:26.742Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.