CVE-2023-53503 (GCVE-0-2023-53503)

Vulnerability from cvelistv5 – Published: 2025-10-01 11:45 – Updated: 2026-05-11 19:46
VLAI
Title
ext4: allow ext4_get_group_info() to fail
Summary
In the Linux kernel, the following vulnerability has been resolved: ext4: allow ext4_get_group_info() to fail Previously, ext4_get_group_info() would treat an invalid group number as BUG(), since in theory it should never happen. However, if a malicious attaker (or fuzzer) modifies the superblock via the block device while it is the file system is mounted, it is possible for s_first_data_block to get set to a very large number. In that case, when calculating the block group of some block number (such as the starting block of a preallocation region), could result in an underflow and very large block group number. Then the BUG_ON check in ext4_get_group_info() would fire, resutling in a denial of service attack that can be triggered by root or someone with write access to the block device. For a quality of implementation perspective, it's best that even if the system administrator does something that they shouldn't, that it will not trigger a BUG. So instead of BUG'ing, ext4_get_group_info() will call ext4_error and return NULL. We also add fallback code in all of the callers of ext4_get_group_info() that it might NULL. Also, since ext4_get_group_info() was already borderline to be an inline function, un-inline it. The results in a next reduction of the compiled text size of ext4 by roughly 2k.
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 7033 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 2f2e09eb15849562aede80ed007658e4504ded26 , < 100c0ad6c04597fefeaaba2bb1827cc015d95067 (git)
Affected: 2f2e09eb15849562aede80ed007658e4504ded26 , < 620a3c28221bb219b81bc0bffd065cc187494302 (git)
Affected: 2f2e09eb15849562aede80ed007658e4504ded26 , < b4319e457d6e3fb33e443efeaf4634fc36e8a9ed (git)
Affected: 2f2e09eb15849562aede80ed007658e4504ded26 , < 31668cebf45adfb6283e465e641c4f5a21b07afa (git)
Affected: 2f2e09eb15849562aede80ed007658e4504ded26 , < 5354b2af34064a4579be8bc0e2f15a7b70f14b5f (git)
guessed Create a notification for this product.
Linux Linux Affected: 3.11
Unaffected: 0 , < 3.11 (semver)
Unaffected: 5.10.181 , ≤ 5.10.* (semver)
Unaffected: 5.15.113 , ≤ 5.15.* (semver)
Unaffected: 6.1.30 , ≤ 6.1.* (semver)
Unaffected: 6.3.4 , ≤ 6.3.* (semver)
Unaffected: 6.4 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ext4/balloc.c",
            "fs/ext4/ext4.h",
            "fs/ext4/ialloc.c",
            "fs/ext4/mballoc.c",
            "fs/ext4/super.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "100c0ad6c04597fefeaaba2bb1827cc015d95067",
              "status": "affected",
              "version": "2f2e09eb15849562aede80ed007658e4504ded26",
              "versionType": "git"
            },
            {
              "lessThan": "620a3c28221bb219b81bc0bffd065cc187494302",
              "status": "affected",
              "version": "2f2e09eb15849562aede80ed007658e4504ded26",
              "versionType": "git"
            },
            {
              "lessThan": "b4319e457d6e3fb33e443efeaf4634fc36e8a9ed",
              "status": "affected",
              "version": "2f2e09eb15849562aede80ed007658e4504ded26",
              "versionType": "git"
            },
            {
              "lessThan": "31668cebf45adfb6283e465e641c4f5a21b07afa",
              "status": "affected",
              "version": "2f2e09eb15849562aede80ed007658e4504ded26",
              "versionType": "git"
            },
            {
              "lessThan": "5354b2af34064a4579be8bc0e2f15a7b70f14b5f",
              "status": "affected",
              "version": "2f2e09eb15849562aede80ed007658e4504ded26",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/ext4/balloc.c",
            "fs/ext4/ext4.h",
            "fs/ext4/ialloc.c",
            "fs/ext4/mballoc.c",
            "fs/ext4/super.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.11"
            },
            {
              "lessThan": "3.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.181",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.113",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.30",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.3.*",
              "status": "unaffected",
              "version": "6.3.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.4",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.181",
                  "versionStartIncluding": "3.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.113",
                  "versionStartIncluding": "3.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.30",
                  "versionStartIncluding": "3.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.3.4",
                  "versionStartIncluding": "3.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.4",
                  "versionStartIncluding": "3.11",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: allow ext4_get_group_info() to fail\n\nPreviously, ext4_get_group_info() would treat an invalid group number\nas BUG(), since in theory it should never happen.  However, if a\nmalicious attaker (or fuzzer) modifies the superblock via the block\ndevice while it is the file system is mounted, it is possible for\ns_first_data_block to get set to a very large number.  In that case,\nwhen calculating the block group of some block number (such as the\nstarting block of a preallocation region), could result in an\nunderflow and very large block group number.  Then the BUG_ON check in\next4_get_group_info() would fire, resutling in a denial of service\nattack that can be triggered by root or someone with write access to\nthe block device.\n\nFor a quality of implementation perspective, it\u0027s best that even if\nthe system administrator does something that they shouldn\u0027t, that it\nwill not trigger a BUG.  So instead of BUG\u0027ing, ext4_get_group_info()\nwill call ext4_error and return NULL.  We also add fallback code in\nall of the callers of ext4_get_group_info() that it might NULL.\n\nAlso, since ext4_get_group_info() was already borderline to be an\ninline function, un-inline it.  The results in a next reduction of the\ncompiled text size of ext4 by roughly 2k."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T19:46:14.267Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/100c0ad6c04597fefeaaba2bb1827cc015d95067"
        },
        {
          "url": "https://git.kernel.org/stable/c/620a3c28221bb219b81bc0bffd065cc187494302"
        },
        {
          "url": "https://git.kernel.org/stable/c/b4319e457d6e3fb33e443efeaf4634fc36e8a9ed"
        },
        {
          "url": "https://git.kernel.org/stable/c/31668cebf45adfb6283e465e641c4f5a21b07afa"
        },
        {
          "url": "https://git.kernel.org/stable/c/5354b2af34064a4579be8bc0e2f15a7b70f14b5f"
        }
      ],
      "title": "ext4: allow ext4_get_group_info() to fail",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2023-53503",
    "datePublished": "2025-10-01T11:45:54.052Z",
    "dateReserved": "2025-10-01T11:39:39.404Z",
    "dateUpdated": "2026-05-11T19:46:14.267Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2023-53503",
      "date": "2026-10-30",
      "epss": "0.00159",
      "percentile": "0.05036"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "fs/ext4/balloc.c",
                  "fs/ext4/ext4.h",
                  "fs/ext4/ialloc.c",
                  "fs/ext4/mballoc.c",
                  "fs/ext4/super.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "100c0ad6c04597fefeaaba2bb1827cc015d95067",
                    "status": "affected",
                    "version": "2f2e09eb15849562aede80ed007658e4504ded26",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "620a3c28221bb219b81bc0bffd065cc187494302",
                    "status": "affected",
                    "version": "2f2e09eb15849562aede80ed007658e4504ded26",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "b4319e457d6e3fb33e443efeaf4634fc36e8a9ed",
                    "status": "affected",
                    "version": "2f2e09eb15849562aede80ed007658e4504ded26",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "31668cebf45adfb6283e465e641c4f5a21b07afa",
                    "status": "affected",
                    "version": "2f2e09eb15849562aede80ed007658e4504ded26",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "5354b2af34064a4579be8bc0e2f15a7b70f14b5f",
                    "status": "affected",
                    "version": "2f2e09eb15849562aede80ed007658e4504ded26",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "fs/ext4/balloc.c",
                  "fs/ext4/ext4.h",
                  "fs/ext4/ialloc.c",
                  "fs/ext4/mballoc.c",
                  "fs/ext4/super.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "3.11"
                  },
                  {
                    "lessThan": "3.11",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "5.10.*",
                    "status": "unaffected",
                    "version": "5.10.181",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "5.15.*",
                    "status": "unaffected",
                    "version": "5.15.113",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.1.*",
                    "status": "unaffected",
                    "version": "6.1.30",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.3.*",
                    "status": "unaffected",
                    "version": "6.3.4",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "6.4",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "4B7B3683-E9CA-4312-979C-328358185649",
                    "versionEndExcluding": "5.10.181",
                    "versionStartIncluding": "3.11",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "F3D5E1B5-AB9D-4ECC-8F11-F3E1BF761E27",
                    "versionEndExcluding": "5.15.113",
                    "versionStartIncluding": "5.11",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "E9430E62-03EA-42E6-9E5E-BD1D5124D107",
                    "versionEndExcluding": "6.1.30",
                    "versionStartIncluding": "5.16",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "26C54BF0-3EED-46D4-92A7-5F07F658B49B",
                    "versionEndExcluding": "6.3.4",
                    "versionStartIncluding": "6.2",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.4:rc1:*:*:*:*:*:*",
                    "matchCriteriaId": "38BC6744-7D25-4C02-9966-B224CD071D30",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: allow ext4_get_group_info() to fail\n\nPreviously, ext4_get_group_info() would treat an invalid group number\nas BUG(), since in theory it should never happen.  However, if a\nmalicious attaker (or fuzzer) modifies the superblock via the block\ndevice while it is the file system is mounted, it is possible for\ns_first_data_block to get set to a very large number.  In that case,\nwhen calculating the block group of some block number (such as the\nstarting block of a preallocation region), could result in an\nunderflow and very large block group number.  Then the BUG_ON check in\next4_get_group_info() would fire, resutling in a denial of service\nattack that can be triggered by root or someone with write access to\nthe block device.\n\nFor a quality of implementation perspective, it\u0027s best that even if\nthe system administrator does something that they shouldn\u0027t, that it\nwill not trigger a BUG.  So instead of BUG\u0027ing, ext4_get_group_info()\nwill call ext4_error and return NULL.  We also add fallback code in\nall of the callers of ext4_get_group_info() that it might NULL.\n\nAlso, since ext4_get_group_info() was already borderline to be an\ninline function, un-inline it.  The results in a next reduction of the\ncompiled text size of ext4 by roughly 2k."
          }
        ],
        "id": "CVE-2023-53503",
        "lastModified": "2026-06-17T06:45:29.170",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 5.5,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.8,
              "impactScore": 3.6,
              "source": "nvd@nist.gov",
              "type": "Primary"
            }
          ]
        },
        "published": "2025-10-01T12:15:53.917",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/100c0ad6c04597fefeaaba2bb1827cc015d95067"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/31668cebf45adfb6283e465e641c4f5a21b07afa"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/5354b2af34064a4579be8bc0e2f15a7b70f14b5f"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/620a3c28221bb219b81bc0bffd065cc187494302"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/b4319e457d6e3fb33e443efeaf4634fc36e8a9ed"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-476"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-06-29T22:24:36+00:00",
      "cve": "CVE-2023-53503",
      "id": "CVE-2023-53503",
      "initial_release_date": "2023-01-01T00:00:00+00:00",
      "product_status:fixed": "559",
      "product_status:known_affected": "112",
      "product_status:known_not_affected": "84",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ext4: allow ext4_get_group_info() to fail",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2023/cve-2023-53503.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-29T02:06:54Z",
      "cve": "CVE-2023-53503",
      "id": "CVE-2023-53503",
      "initial_release_date": "2025-10-01T23:30:05Z",
      "product_status:known_affected": "318",
      "product_status:known_not_affected": "145",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2023-53503",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2023-53503.json",
      "version": "16"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON
How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.