CVE-2026-43076 (GCVE-0-2026-43076)
Vulnerability from cvelistv5
Published
2026-05-06 07:40
Modified
2026-08-05 12:25
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: ocfs2: validate inline data i_size during inode read When reading an inode from disk, ocfs2_validate_inode_block() performs various sanity checks but does not validate the size of inline data. If the filesystem is corrupted, an inode's i_size can exceed the actual inline data capacity (id_count). This causes ocfs2_dir_foreach_blk_id() to iterate beyond the inline data buffer, triggering a use-after-free when accessing directory entries from freed memory. In the syzbot report: - i_size was 1099511627576 bytes (~1TB) - Actual inline data capacity (id_count) is typically <256 bytes - A garbage rec_len (54648) caused ctx->pos to jump out of bounds - This triggered a UAF in ocfs2_check_dir_entry() Fix by adding a validation check in ocfs2_validate_inode_block() to ensure inodes with inline data have i_size <= id_count. This catches the corruption early during inode read and prevents all downstream code from operating on invalid data.
References
Impacted products
Vendor Product Version
Linux Linux Version: 23193e513d1cd69411469f028d56fd175d4a6b07
Version: 23193e513d1cd69411469f028d56fd175d4a6b07
Version: 23193e513d1cd69411469f028d56fd175d4a6b07
Version: 23193e513d1cd69411469f028d56fd175d4a6b07
Version: 23193e513d1cd69411469f028d56fd175d4a6b07
Version: 23193e513d1cd69411469f028d56fd175d4a6b07
Version: 23193e513d1cd69411469f028d56fd175d4a6b07
Version: 23193e513d1cd69411469f028d56fd175d4a6b07
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ocfs2/inode.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "d012c782abcabe68b5b9e71be58a15e9f9d83dc1",
              "status": "affected",
              "version": "23193e513d1cd69411469f028d56fd175d4a6b07",
              "versionType": "git"
            },
            {
              "lessThan": "bcd46bc261b215b3b12c557a978299eafa02ecdd",
              "status": "affected",
              "version": "23193e513d1cd69411469f028d56fd175d4a6b07",
              "versionType": "git"
            },
            {
              "lessThan": "131c0b573e1b467b7d553e9ff38003f1acd8f5f2",
              "status": "affected",
              "version": "23193e513d1cd69411469f028d56fd175d4a6b07",
              "versionType": "git"
            },
            {
              "lessThan": "37f074e65f24f10f8d8df224a572e4cb9e6faf63",
              "status": "affected",
              "version": "23193e513d1cd69411469f028d56fd175d4a6b07",
              "versionType": "git"
            },
            {
              "lessThan": "c1de19e891be3bfb3e1d0c7cf07bbb8fb3b77c1b",
              "status": "affected",
              "version": "23193e513d1cd69411469f028d56fd175d4a6b07",
              "versionType": "git"
            },
            {
              "lessThan": "cd2d765aa7157f852999842af32148128c735d39",
              "status": "affected",
              "version": "23193e513d1cd69411469f028d56fd175d4a6b07",
              "versionType": "git"
            },
            {
              "lessThan": "77d0295725109d77f5854ef5b58c0d06c08168cc",
              "status": "affected",
              "version": "23193e513d1cd69411469f028d56fd175d4a6b07",
              "versionType": "git"
            },
            {
              "lessThan": "1524af3685b35feac76662cc551cbc37bd14775f",
              "status": "affected",
              "version": "23193e513d1cd69411469f028d56fd175d4a6b07",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/ocfs2/inode.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.24"
            },
            {
              "lessThan": "2.6.24",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.258",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.209",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.175",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.136",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.83",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.24",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.14",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.258",
                  "versionStartIncluding": "2.6.24",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.209",
                  "versionStartIncluding": "2.6.24",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.175",
                  "versionStartIncluding": "2.6.24",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.136",
                  "versionStartIncluding": "2.6.24",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.83",
                  "versionStartIncluding": "2.6.24",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.24",
                  "versionStartIncluding": "2.6.24",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.14",
                  "versionStartIncluding": "2.6.24",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "2.6.24",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: validate inline data i_size during inode read\n\nWhen reading an inode from disk, ocfs2_validate_inode_block() performs\nvarious sanity checks but does not validate the size of inline data.  If\nthe filesystem is corrupted, an inode\u0027s i_size can exceed the actual\ninline data capacity (id_count).\n\nThis causes ocfs2_dir_foreach_blk_id() to iterate beyond the inline data\nbuffer, triggering a use-after-free when accessing directory entries from\nfreed memory.\n\nIn the syzbot report:\n  - i_size was 1099511627576 bytes (~1TB)\n  - Actual inline data capacity (id_count) is typically \u003c256 bytes\n  - A garbage rec_len (54648) caused ctx-\u003epos to jump out of bounds\n  - This triggered a UAF in ocfs2_check_dir_entry()\n\nFix by adding a validation check in ocfs2_validate_inode_block() to ensure\ninodes with inline data have i_size \u003c= id_count.  This catches the\ncorruption early during inode read and prevents all downstream code from\noperating on invalid data."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable OCFS2 inode and directory parsing is reached through a locally mounted crafted filesystem image or local directory enumeration, not by network packet processing. A loopback or local block-device image is a reasonable delivery path, so Local is higher and more appropriate than Physical.\nAC:L - The trigger is a deterministic malformed inline-data inode with i_size greater than id_count; syzbot and the fix discussion show reliable crashes without a race. The attacker controls the filesystem metadata, including the malformed size relationship.\nPR:N - Direct mounting of OCFS2 requires CAP_SYS_ADMIN and OCFS2 lacks FS_USERNS_MOUNT, so an unprivileged attacker cannot self-mount it through a user namespace. In the higher-severity crafted-image scenario, the victim/admin performs the privileged mount, so the attacker needs no pre-existing privileges.\nUI:R - Exploitation requires a victim or system component to mount the crafted OCFS2 filesystem and, depending on state, allow mount recovery or directory enumeration to run. That mount/open/enumeration action is user interaction.\nS:U - The impact is within the kernel instance processing the malicious filesystem. There is no VM, IOMMU, or separate security authority boundary crossed.\nC:H - The bug reads past the inline data buffer into freed memory in ocfs2_check_dir_entry, and readdir can process dirent fields and names from that memory. This is a kernel memory-safety issue with plausible high confidentiality impact.\nI:H - Although the observed report is a UAF read, it is a use-after-free over kernel memory during attacker-controlled metadata parsing. Per the required kernel guidance and uncertainty rule, UAF is scored as potentially enabling high integrity compromise.\nA:H - The syzbot report demonstrates a KASAN use-after-free in kernel context, and malformed metadata can repeatedly trigger invalid freed-memory access. A kernel oops or panic is a high availability impact."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:25:47.888Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/d012c782abcabe68b5b9e71be58a15e9f9d83dc1"
        },
        {
          "url": "https://git.kernel.org/stable/c/bcd46bc261b215b3b12c557a978299eafa02ecdd"
        },
        {
          "url": "https://git.kernel.org/stable/c/131c0b573e1b467b7d553e9ff38003f1acd8f5f2"
        },
        {
          "url": "https://git.kernel.org/stable/c/37f074e65f24f10f8d8df224a572e4cb9e6faf63"
        },
        {
          "url": "https://git.kernel.org/stable/c/c1de19e891be3bfb3e1d0c7cf07bbb8fb3b77c1b"
        },
        {
          "url": "https://git.kernel.org/stable/c/cd2d765aa7157f852999842af32148128c735d39"
        },
        {
          "url": "https://git.kernel.org/stable/c/77d0295725109d77f5854ef5b58c0d06c08168cc"
        },
        {
          "url": "https://git.kernel.org/stable/c/1524af3685b35feac76662cc551cbc37bd14775f"
        }
      ],
      "title": "ocfs2: validate inline data i_size during inode read",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43076",
    "datePublished": "2026-05-06T07:40:13.634Z",
    "dateReserved": "2026-05-01T14:12:55.983Z",
    "dateUpdated": "2026-08-05T12:25:47.888Z",
    "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.