CVE-2026-64074 (GCVE-0-2026-64074)

Vulnerability from cvelistv5 – Published: 2026-07-19 15:39 – Updated: 2026-08-05 12:38
VLAI
Title
fs/statmount: fix slab out-of-bounds write in statmount_mnt_idmap
Summary
In the Linux kernel, the following vulnerability has been resolved: fs/statmount: fix slab out-of-bounds write in statmount_mnt_idmap statmount_mnt_idmap() writes one mapping with seq_printf() and then manually advances seq->count to include the NUL separator. If seq_printf() overflows, seq_set_overflow() sets seq->count to seq->size. The manual seq->count++ changes this to seq->size + 1. seq_has_overflowed() then no longer detects the overflow. The corrupted count returns to statmount_string(), which later executes: seq->buf[seq->count++] = '\0'; This causes a 1-byte NULL out-of-bounds write on the dynamically allocated seq buffer. Fix this by checking for overflow immediately after seq_printf().
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: 37c4a9590e1efcae7749682239fc22a330d2d325 , < e37ea2c6f17f273813ea4e8e94c102591d598ce1 (git)
Affected: 37c4a9590e1efcae7749682239fc22a330d2d325 , < 93614949dc86f068e3c32c32cf1ee2a2323177a7 (git)
Affected: 37c4a9590e1efcae7749682239fc22a330d2d325 , < a3bf0f28d4ba16e1f35f8c983bb04426b87e2a78 (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.15
Unaffected: 0 , < 6.15 (semver)
Unaffected: 6.18.34 , ≤ 6.18.* (semver)
Unaffected: 7.0.11 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (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/mnt_idmapping.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "e37ea2c6f17f273813ea4e8e94c102591d598ce1",
              "status": "affected",
              "version": "37c4a9590e1efcae7749682239fc22a330d2d325",
              "versionType": "git"
            },
            {
              "lessThan": "93614949dc86f068e3c32c32cf1ee2a2323177a7",
              "status": "affected",
              "version": "37c4a9590e1efcae7749682239fc22a330d2d325",
              "versionType": "git"
            },
            {
              "lessThan": "a3bf0f28d4ba16e1f35f8c983bb04426b87e2a78",
              "status": "affected",
              "version": "37c4a9590e1efcae7749682239fc22a330d2d325",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/mnt_idmapping.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.15"
            },
            {
              "lessThan": "6.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.34",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.34",
                  "versionStartIncluding": "6.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.11",
                  "versionStartIncluding": "6.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.15",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/statmount: fix slab out-of-bounds write in statmount_mnt_idmap\n\nstatmount_mnt_idmap() writes one mapping with seq_printf() and then\nmanually advances seq-\u003ecount to include the NUL separator.\n\nIf seq_printf() overflows, seq_set_overflow() sets seq-\u003ecount to\nseq-\u003esize. The manual seq-\u003ecount++ changes this to seq-\u003esize + 1.\nseq_has_overflowed() then no longer detects the overflow. The corrupted\ncount returns to statmount_string(), which later executes:\n\n    seq-\u003ebuf[seq-\u003ecount++] = \u0027\\0\u0027;\n\nThis causes a 1-byte NULL out-of-bounds write on the dynamically\nallocated seq buffer.\n\nFix this by checking for overflow immediately after seq_printf()."
        }
      ],
      "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 bug is reachable only through the statmount(2) syscall when requesting mount UID/GID map strings; there is no network, adjacent, or physical entry path to this code.\nAC:L - An attacker fully controls statmount mask, buffer sizing, mount paths/options, and idmap extent values to reliably drive seq_printf() to overflow at the vulnerable count++ site without depending on uncontrollable timing or layout.\nPR:L - Exploitation requires creating or querying an idmapped mount via statmount, which an unprivileged local user can do in their own user/mount namespaces where CAP_SYS_ADMIN is granted by user namespaces.\nUI:N - Triggering the flaw requires only the attacker\u0027s own statmount syscall and crafted namespace/mount setup; no action by another user or victim is needed.\nS:U - Impact is kernel heap corruption and potential privilege escalation within the same kernel security domain, not a cross-boundary escape such as VM guest-to-host.\nC:H - The flaw is a slab out-of-bounds write that corrupts adjacent heap memory; per kernel CVSS guidance, exploitable memory corruption warrants High confidentiality impact even if direct read is not guaranteed.\nI:H - A one-byte out-of-bounds NULL write into adjacent kmalloc slab objects can corrupt kernel metadata and be leveraged for arbitrary memory modification or code execution.\nA:H - Heap corruption from the out-of-bounds write can cause kernel oops/panic or destabilize the system, and memory-corruption bugs are scored as High availability impact."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:38:55.440Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e37ea2c6f17f273813ea4e8e94c102591d598ce1"
        },
        {
          "url": "https://git.kernel.org/stable/c/93614949dc86f068e3c32c32cf1ee2a2323177a7"
        },
        {
          "url": "https://git.kernel.org/stable/c/a3bf0f28d4ba16e1f35f8c983bb04426b87e2a78"
        }
      ],
      "title": "fs/statmount: fix slab out-of-bounds write in statmount_mnt_idmap",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64074",
    "datePublished": "2026-07-19T15:39:49.076Z",
    "dateReserved": "2026-07-19T07:54:57.031Z",
    "dateUpdated": "2026-08-05T12:38:55.440Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-64074",
      "date": "2026-09-21",
      "epss": "0.00127",
      "percentile": "0.02732"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "fs/mnt_idmapping.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "e37ea2c6f17f273813ea4e8e94c102591d598ce1",
                    "status": "affected",
                    "version": "37c4a9590e1efcae7749682239fc22a330d2d325",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "93614949dc86f068e3c32c32cf1ee2a2323177a7",
                    "status": "affected",
                    "version": "37c4a9590e1efcae7749682239fc22a330d2d325",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "a3bf0f28d4ba16e1f35f8c983bb04426b87e2a78",
                    "status": "affected",
                    "version": "37c4a9590e1efcae7749682239fc22a330d2d325",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "fs/mnt_idmapping.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "6.15"
                  },
                  {
                    "lessThan": "6.15",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.18.*",
                    "status": "unaffected",
                    "version": "6.18.34",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.0.*",
                    "status": "unaffected",
                    "version": "7.0.11",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "7.1",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "89E9B97C-FD82-4D2E-8426-3A1A703B2ED7",
                    "versionEndExcluding": "6.18.34",
                    "versionStartIncluding": "6.15",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "0520D091-FC52-4A50-AF07-70AE7D08B750",
                    "versionEndExcluding": "7.0.11",
                    "versionStartIncluding": "6.19",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*",
                    "matchCriteriaId": "B1EF7059-E670-45F4-B422-54C40FA86390",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*",
                    "matchCriteriaId": "0D38F0BF-A728-4133-A358-D44A2F7EE6D6",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*",
                    "matchCriteriaId": "EC732D08-5F7B-46D9-B154-E60C7F4F0A97",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*",
                    "matchCriteriaId": "E5910A9D-F60A-409A-B486-FE66BFEBA9B9",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/statmount: fix slab out-of-bounds write in statmount_mnt_idmap\n\nstatmount_mnt_idmap() writes one mapping with seq_printf() and then\nmanually advances seq-\u003ecount to include the NUL separator.\n\nIf seq_printf() overflows, seq_set_overflow() sets seq-\u003ecount to\nseq-\u003esize. The manual seq-\u003ecount++ changes this to seq-\u003esize + 1.\nseq_has_overflowed() then no longer detects the overflow. The corrupted\ncount returns to statmount_string(), which later executes:\n\n    seq-\u003ebuf[seq-\u003ecount++] = \u0027\\0\u0027;\n\nThis causes a 1-byte NULL out-of-bounds write on the dynamically\nallocated seq buffer.\n\nFix this by checking for overflow immediately after seq_printf()."
          }
        ],
        "id": "CVE-2026-64074",
        "lastModified": "2026-09-03T14:47:02.987",
        "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": "2026-07-19T16:17:48.010",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/93614949dc86f068e3c32c32cf1ee2a2323177a7"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/a3bf0f28d4ba16e1f35f8c983bb04426b87e2a78"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/e37ea2c6f17f273813ea4e8e94c102591d598ce1"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-787"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "None",
      "current_release_date": "2026-07-21T07:52:33+00:00",
      "cve": "CVE-2026-64074",
      "id": "CVE-2026-64074",
      "initial_release_date": "2026-07-19T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: fs/statmount: fix slab out-of-bounds write in statmount_mnt_idmap",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64074.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-08-05T00:34:03Z",
      "cve": "CVE-2026-64074",
      "id": "CVE-2026-64074",
      "initial_release_date": "2026-07-21T13:00:10Z",
      "product_status:known_not_affected": "296",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-64074",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-64074.json",
      "version": "3"
    }
  }
}



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.


Detection rules are retrieved from Rulezet.


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.