CVE-2026-31484 (GCVE-0-2026-31484)

Vulnerability from cvelistv5 – Published: 2026-04-22 13:54 – Updated: 2026-08-05 12:22
VLAI
Title
io_uring/fdinfo: fix OOB read in SQE_MIXED wrap check
Summary
In the Linux kernel, the following vulnerability has been resolved: io_uring/fdinfo: fix OOB read in SQE_MIXED wrap check __io_uring_show_fdinfo() iterates over pending SQEs and, for 128-byte SQEs on an IORING_SETUP_SQE_MIXED ring, needs to detect when the second half of the SQE would be past the end of the sq_sqes array. The current check tests (++sq_head & sq_mask) == 0, but sq_head is only incremented when a 128-byte SQE is encountered, not on every iteration. The actual array index is sq_idx = (i + sq_head) & sq_mask, which can be sq_mask (the last slot) while the wrap check passes. Fix by checking sq_idx directly. Keep the sq_head increment so the loop still skips the second half of the 128-byte SQE on the next iteration.
Severity
7.1 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 1cba30bf9fdd6c982708f3587f609a30c370d889 , < ba21ab247a5be5382da7464b95afbe5f0e9aa503 (git)
Affected: 1cba30bf9fdd6c982708f3587f609a30c370d889 , < 5170efd9c344c68a8075dcb8ed38d3f8a60e7ed4 (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.19
Unaffected: 0 , < 6.19 (semver)
Unaffected: 6.19.11 , ≤ 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": [
            "io_uring/fdinfo.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ba21ab247a5be5382da7464b95afbe5f0e9aa503",
              "status": "affected",
              "version": "1cba30bf9fdd6c982708f3587f609a30c370d889",
              "versionType": "git"
            },
            {
              "lessThan": "5170efd9c344c68a8075dcb8ed38d3f8a60e7ed4",
              "status": "affected",
              "version": "1cba30bf9fdd6c982708f3587f609a30c370d889",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "io_uring/fdinfo.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.19"
            },
            {
              "lessThan": "6.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.11",
              "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": "6.19.11",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/fdinfo: fix OOB read in SQE_MIXED wrap check\n\n__io_uring_show_fdinfo() iterates over pending SQEs and, for 128-byte\nSQEs on an IORING_SETUP_SQE_MIXED ring, needs to detect when the second\nhalf of the SQE would be past the end of the sq_sqes array. The current\ncheck tests (++sq_head \u0026 sq_mask) == 0, but sq_head is only incremented\nwhen a 128-byte SQE is encountered, not on every iteration. The actual\narray index is sq_idx = (i + sq_head) \u0026 sq_mask, which can be sq_mask\n(the last slot) while the wrap check passes.\n\nFix by checking sq_idx directly. Keep the sq_head increment so the loop\nstill skips the second half of the 128-byte SQE on the next iteration."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable path is reached locally by creating an io_uring instance and reading its procfs fdinfo entry; there is no network or adjacent attack surface.\nAC:L - The attacker controls the ring setup flags, SQ tail, SQ array mapping, and 128-byte SQE opcode needed to place a mixed SQE at the last physical slot. No race or external timing condition is required, and transient lock contention can be retried.\nPR:L - A normal unprivileged local user can use io_uring when the default io_uring sysctl allows it and can read /proc/self/fdinfo for its own fd. No real root or init-namespace capability is required.\nUI:N - The attacker triggers the bug by reading their own fdinfo file. No victim action is needed.\nS:U - The issue is a local kernel memory access bug within the same kernel security authority. It does not cross a VM, IOMMU, or other separate security scope boundary.\nC:H - The bug prints the second half of a 128-byte SQE by dereferencing up to 64 bytes past the SQE array, exposing adjacent kernel memory through procfs. The leak is attacker-triggerable and repeatable, so the highest defensible confidentiality impact is high.\nI:N - The vulnerable operation is an out-of-bounds read used for fdinfo printing and does not write to kernel memory or directly modify protected state.\nA:H - The same out-of-bounds kernel dereference can cross the end of the SQE allocation or a vmap-backed region and fault/oops depending on allocation layout. An unprivileged attacker can repeatedly trigger the path, so availability impact is high."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:22:59.333Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ba21ab247a5be5382da7464b95afbe5f0e9aa503"
        },
        {
          "url": "https://git.kernel.org/stable/c/5170efd9c344c68a8075dcb8ed38d3f8a60e7ed4"
        }
      ],
      "title": "io_uring/fdinfo: fix OOB read in SQE_MIXED wrap check",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31484",
    "datePublished": "2026-04-22T13:54:10.223Z",
    "dateReserved": "2026-03-09T15:48:24.101Z",
    "dateUpdated": "2026-08-05T12:22:59.333Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-31484",
      "date": "2026-09-29",
      "epss": "0.00156",
      "percentile": "0.0409"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "io_uring/fdinfo.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "ba21ab247a5be5382da7464b95afbe5f0e9aa503",
                    "status": "affected",
                    "version": "1cba30bf9fdd6c982708f3587f609a30c370d889",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "5170efd9c344c68a8075dcb8ed38d3f8a60e7ed4",
                    "status": "affected",
                    "version": "1cba30bf9fdd6c982708f3587f609a30c370d889",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "io_uring/fdinfo.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "6.19"
                  },
                  {
                    "lessThan": "6.19",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.19.*",
                    "status": "unaffected",
                    "version": "6.19.11",
                    "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": "5054C854-C253-4020-BD2E-2BDA121E424C",
                    "versionEndExcluding": "6.19.11",
                    "versionStartIncluding": "6.19.1",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.19:-:*:*:*:*:*:*",
                    "matchCriteriaId": "35C8A871-4971-433E-A046-FC9F7B7D190A",
                    "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\nio_uring/fdinfo: fix OOB read in SQE_MIXED wrap check\n\n__io_uring_show_fdinfo() iterates over pending SQEs and, for 128-byte\nSQEs on an IORING_SETUP_SQE_MIXED ring, needs to detect when the second\nhalf of the SQE would be past the end of the sq_sqes array. The current\ncheck tests (++sq_head \u0026 sq_mask) == 0, but sq_head is only incremented\nwhen a 128-byte SQE is encountered, not on every iteration. The actual\narray index is sq_idx = (i + sq_head) \u0026 sq_mask, which can be sq_mask\n(the last slot) while the wrap check passes.\n\nFix by checking sq_idx directly. Keep the sq_head increment so the loop\nstill skips the second half of the 128-byte SQE on the next iteration."
          }
        ],
        "id": "CVE-2026-31484",
        "lastModified": "2026-06-17T10:33:49.827",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.1,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "NONE",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.8,
              "impactScore": 5.2,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-04-22T14:16:45.800",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/5170efd9c344c68a8075dcb8ed38d3f8a60e7ed4"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/ba21ab247a5be5382da7464b95afbe5f0e9aa503"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-125"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "None",
      "current_release_date": "2026-06-28T11:57:37+00:00",
      "cve": "CVE-2026-31484",
      "id": "CVE-2026-31484",
      "initial_release_date": "2026-04-22T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: io_uring/fdinfo: fix OOB read in SQE_MIXED wrap check",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-31484.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-06T01:24:52Z",
      "cve": "CVE-2026-31484",
      "id": "CVE-2026-31484",
      "initial_release_date": "2026-04-23T01:25:38Z",
      "product_status:known_not_affected": "315",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-31484",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-31484.json",
      "version": "5"
    }
  }
}



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.