CVE-2026-31666 (GCVE-0-2026-31666)

Vulnerability from cvelistv5 – Published: 2026-04-24 14:45 – Updated: 2026-08-05 12:24
VLAI
Title
btrfs: fix incorrect return value after changing leaf in lookup_extent_data_ref()
Summary
In the Linux kernel, the following vulnerability has been resolved: btrfs: fix incorrect return value after changing leaf in lookup_extent_data_ref() After commit 1618aa3c2e01 ("btrfs: simplify return variables in lookup_extent_data_ref()"), the err and ret variables were merged into a single ret variable. However, when btrfs_next_leaf() returns 0 (success), ret is overwritten from -ENOENT to 0. If the first key in the next leaf does not match (different objectid or type), the function returns 0 instead of -ENOENT, making the caller believe the lookup succeeded when it did not. This can lead to operations on the wrong extent tree item, potentially causing extent tree corruption. Fix this by returning -ENOENT directly when the key does not match, instead of relying on the ret variable.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 1618aa3c2e0163f5ac34d514ae89474521910536 , < 4125a194db4a6cf91f619f38788272651cb97dce (git)
Affected: 1618aa3c2e0163f5ac34d514ae89474521910536 , < 450e6a685d0cad95b15f8af152057bd0bf79f50b (git)
Affected: 1618aa3c2e0163f5ac34d514ae89474521910536 , < ab1e022379c3c811aa72da8eb0c7507859a1d0f5 (git)
Affected: 1618aa3c2e0163f5ac34d514ae89474521910536 , < 316fb1b3169efb081d2db910cbbfef445afa03b9 (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.10
Unaffected: 0 , < 6.10 (semver)
Unaffected: 6.12.82 , ≤ 6.12.* (semver)
Unaffected: 6.18.23 , ≤ 6.18.* (semver)
Unaffected: 6.19.13 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (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/btrfs/extent-tree.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "4125a194db4a6cf91f619f38788272651cb97dce",
              "status": "affected",
              "version": "1618aa3c2e0163f5ac34d514ae89474521910536",
              "versionType": "git"
            },
            {
              "lessThan": "450e6a685d0cad95b15f8af152057bd0bf79f50b",
              "status": "affected",
              "version": "1618aa3c2e0163f5ac34d514ae89474521910536",
              "versionType": "git"
            },
            {
              "lessThan": "ab1e022379c3c811aa72da8eb0c7507859a1d0f5",
              "status": "affected",
              "version": "1618aa3c2e0163f5ac34d514ae89474521910536",
              "versionType": "git"
            },
            {
              "lessThan": "316fb1b3169efb081d2db910cbbfef445afa03b9",
              "status": "affected",
              "version": "1618aa3c2e0163f5ac34d514ae89474521910536",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/btrfs/extent-tree.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.10"
            },
            {
              "lessThan": "6.10",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.82",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.23",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.13",
              "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": "6.12.82",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.23",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.13",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix incorrect return value after changing leaf in lookup_extent_data_ref()\n\nAfter commit 1618aa3c2e01 (\"btrfs: simplify return variables in\nlookup_extent_data_ref()\"), the err and ret variables were merged into\na single ret variable. However, when btrfs_next_leaf() returns 0\n(success), ret is overwritten from -ENOENT to 0. If the first key in\nthe next leaf does not match (different objectid or type), the function\nreturns 0 instead of -ENOENT, making the caller believe the lookup\nsucceeded when it did not. This can lead to operations on the wrong\nextent tree item, potentially causing extent tree corruption.\n\nFix this by returning -ENOENT directly when the key does not match,\ninstead of relying on the ret variable."
        }
      ],
      "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 vulnerable Btrfs extent-reference code is reached through local filesystem syscalls such as reflink/dedupe, truncate, unlink, and hole punching on a writable mounted Btrfs filesystem.\nAC:L - The trigger depends on attacker-shaped filesystem metadata and ordinary repeated file operations, not on a race or condition outside attacker control; when uncertain, the lower-complexity value is appropriate.\nPR:L - A basic unprivileged local user with write access to files on the Btrfs mount can exercise the relevant paths; no real root or init-namespace capability is required.\nUI:N - No separate victim action is required after the attacker has local access to a writable Btrfs filesystem; the attacker can issue the file operations directly.\nS:U - The impact remains within the local kernel/filesystem security authority and does not cross a VM, IOMMU, or similar security boundary.\nC:H - Incorrectly deleting or decrementing the wrong extent data reference can corrupt Btrfs extent ownership, plausibly causing stale or unrelated file data exposure through block reuse or aliasing.\nI:H - The bug can operate on the wrong extent tree item and corrupt filesystem metadata, plausibly enabling corruption or loss of arbitrary file data beyond the attacker\u0027s own intended files.\nA:H - The corrupted extent tree path can trigger transaction aborts, read-only remounts, BUG_ON/oops conditions, or persistent filesystem corruption, causing high availability impact."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:24:16.096Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/4125a194db4a6cf91f619f38788272651cb97dce"
        },
        {
          "url": "https://git.kernel.org/stable/c/450e6a685d0cad95b15f8af152057bd0bf79f50b"
        },
        {
          "url": "https://git.kernel.org/stable/c/ab1e022379c3c811aa72da8eb0c7507859a1d0f5"
        },
        {
          "url": "https://git.kernel.org/stable/c/316fb1b3169efb081d2db910cbbfef445afa03b9"
        }
      ],
      "title": "btrfs: fix incorrect return value after changing leaf in lookup_extent_data_ref()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31666",
    "datePublished": "2026-04-24T14:45:15.271Z",
    "dateReserved": "2026-03-09T15:48:24.129Z",
    "dateUpdated": "2026-08-05T12:24:16.096Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-31666",
      "date": "2026-09-28",
      "epss": "0.00175",
      "percentile": "0.06254"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "fs/btrfs/extent-tree.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "4125a194db4a6cf91f619f38788272651cb97dce",
                    "status": "affected",
                    "version": "1618aa3c2e0163f5ac34d514ae89474521910536",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "450e6a685d0cad95b15f8af152057bd0bf79f50b",
                    "status": "affected",
                    "version": "1618aa3c2e0163f5ac34d514ae89474521910536",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "ab1e022379c3c811aa72da8eb0c7507859a1d0f5",
                    "status": "affected",
                    "version": "1618aa3c2e0163f5ac34d514ae89474521910536",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "316fb1b3169efb081d2db910cbbfef445afa03b9",
                    "status": "affected",
                    "version": "1618aa3c2e0163f5ac34d514ae89474521910536",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "fs/btrfs/extent-tree.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "6.10"
                  },
                  {
                    "lessThan": "6.10",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.12.*",
                    "status": "unaffected",
                    "version": "6.12.82",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.18.*",
                    "status": "unaffected",
                    "version": "6.18.23",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.19.*",
                    "status": "unaffected",
                    "version": "6.19.13",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "7.0",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "BBC7140F-5869-4604-97EE-EFD35C33303F",
                    "versionEndExcluding": "6.12.82",
                    "versionStartIncluding": "6.10.1",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "E9E09FDD-9EE3-4A56-92E2-2B30AFD0072F",
                    "versionEndExcluding": "6.18.23",
                    "versionStartIncluding": "6.13",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "1490EF9B-9080-481C-8D22-1306AAE664E4",
                    "versionEndExcluding": "6.19.13",
                    "versionStartIncluding": "6.19",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.10:-:*:*:*:*:*:*",
                    "matchCriteriaId": "9EA80796-744E-45F5-8632-2AB4F7889FCD",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*",
                    "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*",
                    "matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*",
                    "matchCriteriaId": "F666C8D8-6538-46D4-B318-87610DE64C34",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*",
                    "matchCriteriaId": "02259FDA-961B-47BC-AE7F-93D7EC6E90C2",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*",
                    "matchCriteriaId": "58A9FEFF-C040-420D-8F0A-BFDAAA1DF258",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*",
                    "matchCriteriaId": "1D2315C0-D46F-4F85-9754-F9E5E11374A6",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*",
                    "matchCriteriaId": "512EE3A8-A590-4501-9A94-5D4B268D6138",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix incorrect return value after changing leaf in lookup_extent_data_ref()\n\nAfter commit 1618aa3c2e01 (\"btrfs: simplify return variables in\nlookup_extent_data_ref()\"), the err and ret variables were merged into\na single ret variable. However, when btrfs_next_leaf() returns 0\n(success), ret is overwritten from -ENOENT to 0. If the first key in\nthe next leaf does not match (different objectid or type), the function\nreturns 0 instead of -ENOENT, making the caller believe the lookup\nsucceeded when it did not. This can lead to operations on the wrong\nextent tree item, potentially causing extent tree corruption.\n\nFix this by returning -ENOENT directly when the key does not match,\ninstead of relying on the ret variable."
          }
        ],
        "id": "CVE-2026-31666",
        "lastModified": "2026-06-17T10:34:11.820",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.8,
              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-04-24T15:16:46.290",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/316fb1b3169efb081d2db910cbbfef445afa03b9"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/4125a194db4a6cf91f619f38788272651cb97dce"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/450e6a685d0cad95b15f8af152057bd0bf79f50b"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/ab1e022379c3c811aa72da8eb0c7507859a1d0f5"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "NVD-CWE-noinfo"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-07-02T19:11:11+00:00",
      "cve": "CVE-2026-31666",
      "id": "CVE-2026-31666",
      "initial_release_date": "2026-04-24T00:00:00+00:00",
      "product_status:known_affected": "260",
      "product_status:known_not_affected": "14",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: btrfs: fix incorrect return value after changing leaf in lookup_extent_data_ref()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-31666.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-11T01:29:39Z",
      "cve": "CVE-2026-31666",
      "id": "CVE-2026-31666",
      "initial_release_date": "2026-04-25T01:36:36Z",
      "product_status:first_fixed": "2",
      "product_status:known_affected": "394",
      "product_status:known_not_affected": "392",
      "product_status:recommended": "172",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-31666",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-31666.json",
      "version": "8"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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.



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.