GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

CVE-2025-37956 (GCVE-0-2025-37956)

Vulnerability from cvelistv5 – Published: 2025-05-20 16:01 – Updated: 2026-08-05 11:58
VLAI
Title
ksmbd: prevent rename with empty string
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: prevent rename with empty string Client can send empty newname string to ksmbd server. It will cause a kernel oops from d_alloc. This patch return the error when attempting to rename a file or directory with an empty new name string.
Severity
8.8 (High)
CVSS:3.1/AV:N/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: 0626e6641f6b467447c81dd7678a69c66f7746cf , < 6ee551672c8cf36108b0cfba92ec0c7c28ac3439 (git)
Affected: 0626e6641f6b467447c81dd7678a69c66f7746cf , < c57301e332cc413fe0a7294a90725f4e21e9549d (git)
Affected: 0626e6641f6b467447c81dd7678a69c66f7746cf , < d7f2c00acb1ef64304fd40ac507e9213ff1d9b5c (git)
Affected: 0626e6641f6b467447c81dd7678a69c66f7746cf , < 53e3e5babc0963a92d856a5ec0ce92c59f54bc12 (git)
guessed Create a notification for this product.
Linux Linux Affected: 5.15
Unaffected: 0 , < 5.15 (semver)
Unaffected: 6.6.91 , ≤ 6.6.* (semver)
Unaffected: 6.12.29 , ≤ 6.12.* (semver)
Unaffected: 6.14.7 , ≤ 6.14.* (semver)
Unaffected: 6.15 , ≤ * (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/smb/server/smb2pdu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "6ee551672c8cf36108b0cfba92ec0c7c28ac3439",
              "status": "affected",
              "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
              "versionType": "git"
            },
            {
              "lessThan": "c57301e332cc413fe0a7294a90725f4e21e9549d",
              "status": "affected",
              "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
              "versionType": "git"
            },
            {
              "lessThan": "d7f2c00acb1ef64304fd40ac507e9213ff1d9b5c",
              "status": "affected",
              "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
              "versionType": "git"
            },
            {
              "lessThan": "53e3e5babc0963a92d856a5ec0ce92c59f54bc12",
              "status": "affected",
              "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/smb2pdu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.15"
            },
            {
              "lessThan": "5.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.91",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.29",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.14.*",
              "status": "unaffected",
              "version": "6.14.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.15",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.91",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.29",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.14.7",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.15",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: prevent rename with empty string\n\nClient can send empty newname string to ksmbd server.\nIt will cause a kernel oops from d_alloc.\nThis patch return the error when attempting to rename\na file or directory with an empty new name string."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - ksmbd is the in-kernel SMB server; the malformed FILE_RENAME_INFORMATION request arrives over TCP/445 (or SMB-Direct) from a remote client. No local access is involved.\nAC:L - The attacker deterministically triggers the uninitialized-qstr dereference by sending one SET_INFO request with FileNameLength=2 containing a UTF-16 NUL; no race or unpredictable precondition is required, and the stack residue that shapes the outcome is influenced by the attacker\u0027s own preceding requests on the same ksmbd worker.\nPR:L - smb2_set_info requires an established session, a tree connect to a writable share, and an open handle with FILE_DELETE access, so a low-privileged authenticated SMB account (or a guest-mapped session on guest-enabled shares) is needed. This matches sibling post-auth ksmbd CVEs such as CVE-2025-22040/22041.\nUI:N - The server processes the crafted rename request automatically in its worker thread; no action by any local user or administrator is needed.\nS:U - The wild read, dentry corruption and crash all occur within the kernel\u0027s own security authority; no VM, IOMMU or sandbox boundary is crossed.\nC:H - __d_alloc() memcpy\u0027s from an uninitialized kernel-stack pointer with an uncontrolled length \u2014 an unbounded out-of-bounds read whose contents become the new dentry name, which the attacker can then read back over SMB via directory enumeration, disclosing kernel heap/stack data and pointers.\nI:H - The rename completes against a target derived from uninitialized kernel memory and leaves a dentry cached with a bogus d_name.len driving later name-switching memcpy\u0027s; on 32-bit ksmbd builds the `size + name-\u003elen` computation in __d_alloc() overflows, producing an undersized allocation followed by a multi-gigabyte memcpy \u2014 a heap write primitive.\nA:H - The commit states the empty name causes a kernel oops from d_alloc; a remote client can repeat the request at will to keep panicking the server, so availability loss is total."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T11:58:38.144Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/6ee551672c8cf36108b0cfba92ec0c7c28ac3439"
        },
        {
          "url": "https://git.kernel.org/stable/c/c57301e332cc413fe0a7294a90725f4e21e9549d"
        },
        {
          "url": "https://git.kernel.org/stable/c/d7f2c00acb1ef64304fd40ac507e9213ff1d9b5c"
        },
        {
          "url": "https://git.kernel.org/stable/c/53e3e5babc0963a92d856a5ec0ce92c59f54bc12"
        }
      ],
      "title": "ksmbd: prevent rename with empty string",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-37956",
    "datePublished": "2025-05-20T16:01:49.865Z",
    "dateReserved": "2025-04-16T04:51:23.974Z",
    "dateUpdated": "2026-08-05T11:58:38.144Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2025-37956",
      "date": "2026-09-19",
      "epss": "0.00354",
      "percentile": "0.29239"
    },
    "microsoft_vex": {
      "current_release_date": "2026-02-18T02:53:39.000Z",
      "cve": "CVE-2025-37956",
      "id": "msrc_CVE-2025-37956",
      "initial_release_date": "2025-05-02T00:00:00.000Z",
      "product_status:fixed": "2",
      "product_status:known_affected": "2",
      "product_status:known_not_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "ksmbd: prevent rename with empty string",
      "url": "https://msrc.microsoft.com/csaf/vex/2025/msrc_cve-2025-37956.json",
      "version": "4"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "fs/smb/server/smb2pdu.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "6ee551672c8cf36108b0cfba92ec0c7c28ac3439",
                    "status": "affected",
                    "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "c57301e332cc413fe0a7294a90725f4e21e9549d",
                    "status": "affected",
                    "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "d7f2c00acb1ef64304fd40ac507e9213ff1d9b5c",
                    "status": "affected",
                    "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "53e3e5babc0963a92d856a5ec0ce92c59f54bc12",
                    "status": "affected",
                    "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "fs/smb/server/smb2pdu.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "5.15"
                  },
                  {
                    "lessThan": "5.15",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.6.*",
                    "status": "unaffected",
                    "version": "6.6.91",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.12.*",
                    "status": "unaffected",
                    "version": "6.12.29",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.14.*",
                    "status": "unaffected",
                    "version": "6.14.7",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "6.15",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "A0BB0418-DE28-49B6-BEE6-5D5AA1D70BCF",
                    "versionEndExcluding": "6.6.91",
                    "versionStartIncluding": "5.15",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "7215ABCF-8EB1-46CD-8872-8BCE4890E579",
                    "versionEndExcluding": "6.12.29",
                    "versionStartIncluding": "6.7",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "5715A6F5-A34A-4B27-8A64-82825E963995",
                    "versionEndExcluding": "6.14.7",
                    "versionStartIncluding": "6.13",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.15:rc1:*:*:*:*:*:*",
                    "matchCriteriaId": "8D465631-2980-487A-8E65-40AE2B9F8ED1",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.15:rc2:*:*:*:*:*:*",
                    "matchCriteriaId": "4C9D071F-B28E-46EC-AC61-22B913390211",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.15:rc3:*:*:*:*:*:*",
                    "matchCriteriaId": "13FC0DDE-E513-465E-9E81-515702D49B74",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.15:rc4:*:*:*:*:*:*",
                    "matchCriteriaId": "8C7B5B0E-4EEB-48F5-B4CF-0935A7633845",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.15:rc5:*:*:*:*:*:*",
                    "matchCriteriaId": "2D240580-3048-49B2-9E27-F115A9DF8224",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: prevent rename with empty string\n\nClient can send empty newname string to ksmbd server.\nIt will cause a kernel oops from d_alloc.\nThis patch return the error when attempting to rename\na file or directory with an empty new name string."
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ksmbd: impide renombrar con una cadena vac\u00eda. El cliente puede enviar una cadena vac\u00eda de nombre nuevo al servidor ksmbd. Esto provocar\u00e1 un error de kernel desde d_alloc. Este parche devuelve el error al intentar renombrar un archivo o directorio con una cadena vac\u00eda de nombre nuevo."
          }
        ],
        "id": "CVE-2025-37956",
        "lastModified": "2026-07-30T06:22:37.317",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 8.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 2.8,
              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            },
            {
              "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": "2025-05-20T16:15:33.813",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/53e3e5babc0963a92d856a5ec0ce92c59f54bc12"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/6ee551672c8cf36108b0cfba92ec0c7c28ac3439"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/c57301e332cc413fe0a7294a90725f4e21e9549d"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/d7f2c00acb1ef64304fd40ac507e9213ff1d9b5c"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Modified",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "NVD-CWE-noinfo"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "None",
      "current_release_date": "2026-06-30T10:25:37+00:00",
      "cve": "CVE-2025-37956",
      "id": "CVE-2025-37956",
      "initial_release_date": "2025-05-20T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ksmbd: prevent rename with empty string",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-37956.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.