CVE-2025-39933 (GCVE-0-2025-39933)

Vulnerability from cvelistv5 – Published: 2025-10-04 07:30 – Updated: 2026-10-30 12:22
VLAI
Title
smb: client: let recv_done verify data_offset, data_length and remaining_data_length
Summary
In the Linux kernel, the following vulnerability has been resolved: smb: client: let recv_done verify data_offset, data_length and remaining_data_length This is inspired by the related server fixes.
Severity
9.4 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-06-10 20:40 UTC
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6639 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: f198186aa9bbd60fae7a2061f4feec614d880299 , < fdc23a47be015fba915c4f9dfd43c65ad4829a35 (git)
Affected: f198186aa9bbd60fae7a2061f4feec614d880299 , < f23d5c6b7540ec9b1e73a8ea3b2ae9045248d728 (git)
Affected: f198186aa9bbd60fae7a2061f4feec614d880299 , < 241e58de23e7c1bbb9bee526c17d9a0f2a90fbad (git)
Affected: f198186aa9bbd60fae7a2061f4feec614d880299 , < 581fb78e0388b78911b0c920e4073737090c8b5f (git)
Affected: f198186aa9bbd60fae7a2061f4feec614d880299 , < f57e53ea252363234f86674db475839e5b87102e (git)
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Linux Linux Affected: 4.16
Unaffected: 0 , < 4.16 (semver)
Unaffected: 6.1.191 , ≤ 6.1.* (semver)
Unaffected: 6.6.160 , ≤ 6.6.* (semver)
Unaffected: 6.12.114 , ≤ 6.12.* (semver)
Unaffected: 6.16.9 , ≤ 6.16.* (semver)
Unaffected: 6.17 , ≤ * (original_commit_for_fix)
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                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-06-10T20:40:59.041091Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-06-11T17:37:51.386Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "Linux",
              "programFiles": [
                "fs/smb/client/smbdirect.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "lessThan": "fdc23a47be015fba915c4f9dfd43c65ad4829a35",
                  "status": "affected",
                  "version": "f198186aa9bbd60fae7a2061f4feec614d880299",
                  "versionType": "git"
                },
                {
                  "lessThan": "f23d5c6b7540ec9b1e73a8ea3b2ae9045248d728",
                  "status": "affected",
                  "version": "f198186aa9bbd60fae7a2061f4feec614d880299",
                  "versionType": "git"
                },
                {
                  "lessThan": "241e58de23e7c1bbb9bee526c17d9a0f2a90fbad",
                  "status": "affected",
                  "version": "f198186aa9bbd60fae7a2061f4feec614d880299",
                  "versionType": "git"
                },
                {
                  "lessThan": "581fb78e0388b78911b0c920e4073737090c8b5f",
                  "status": "affected",
                  "version": "f198186aa9bbd60fae7a2061f4feec614d880299",
                  "versionType": "git"
                },
                {
                  "lessThan": "f57e53ea252363234f86674db475839e5b87102e",
                  "status": "affected",
                  "version": "f198186aa9bbd60fae7a2061f4feec614d880299",
                  "versionType": "git"
                }
              ]
            },
            {
              "defaultStatus": "affected",
              "product": "Linux",
              "programFiles": [
                "fs/smb/client/smbdirect.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "status": "affected",
                  "version": "4.16"
                },
                {
                  "lessThan": "4.16",
                  "status": "unaffected",
                  "version": "0",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.1.*",
                  "status": "unaffected",
                  "version": "6.1.191",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.6.*",
                  "status": "unaffected",
                  "version": "6.6.160",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.12.*",
                  "status": "unaffected",
                  "version": "6.12.114",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.16.*",
                  "status": "unaffected",
                  "version": "6.16.9",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "*",
                  "status": "unaffected",
                  "version": "6.17",
                  "versionType": "original_commit_for_fix"
                }
              ]
            }
          ],
          "cpeApplicability": [
            {
              "nodes": [
                {
                  "cpeMatch": [
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.1.191",
                      "versionStartIncluding": "4.16",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.6.160",
                      "versionStartIncluding": "4.16",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.12.114",
                      "versionStartIncluding": "4.16",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.16.9",
                      "versionStartIncluding": "4.16",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.17",
                      "versionStartIncluding": "4.16",
                      "vulnerable": true
                    }
                  ],
                  "negate": false,
                  "operator": "OR"
                }
              ]
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: let recv_done verify data_offset, data_length and remaining_data_length\n\nThis is inspired by the related server fixes."
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "baseScore": 9.4,
                "baseSeverity": "CRITICAL",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H",
                "version": "3.1"
              },
              "scenarios": [
                {
                  "lang": "en",
                  "value": "AV:N - The vulnerable code parses `smbdirect_data_transfer` headers received directly from a remote SMB server over RDMA, and iWARP/RoCEv2 are routable over ordinary IP networks (soft-iWARP/soft-RoCE need no special hardware). A malicious, compromised, or spoofed SMB Direct peer reaches `recv_done()` purely over the network.\nAC:L - The attacker writes `data_offset`/`data_length` as plain header fields in a single crafted data-transfer message; there is no race, no memory-layout precondition, and the out-of-bounds read is deterministic and repeatable at an offset of the attacker\u0027s choosing.\nPR:N - `recv_done()` switches to `SMBDIRECT_EXPECT_DATA_TRANSFER` as soon as the unauthenticated transport-level SMBD negotiate completes, so the malformed packet is processed before SMB2 NEGOTIATE/SESSION_SETUP and before any signing or encryption is established \u2014 the peer needs no credentials on the client.\nUI:N - Once an SMB Direct mount exists (including automounts, fstab, DFS referrals, and automatic reconnects), a hostile or compromised server can send the crafted frame at any time and the client processes it automatically in its receive-completion and demultiplex paths. No administrator or user action is required at the moment of attack.\nS:U - The out-of-bounds access, the disclosed data, and the resulting fault are all confined to the client kernel\u0027s own security authority; no hypervisor, IOMMU, or sandbox boundary is crossed.\nC:H - The unvalidated 32-bit `data_offset` makes `copy_to_iter()` read from an attacker-chosen address up to 4 GiB past a ~2 KB receive-buffer slab object, and the inflated `data_length` keeps that buffer at the queue head so `offset` advances on each call \u2014 allowing a remote peer to stream out large amounts of kernel memory, which is then delivered to userspace as SMB response/file content.\nI:L - There is no out-of-bounds write, but the client assembles and parses SMB2 responses built from out-of-bounds kernel memory, so connection state, file metadata, and page-cache contents returned to applications are driven by data the attacker caused the kernel to read from outside the intended buffer.\nA:H - A large `data_offset` faults on unmapped memory or a vmalloc guard page in the demultiplex/softirq path, and an inflated `data_length` desynchronizes `reassembly.data_length` so `_get_first_reassembly()` returns NULL and is immediately dereferenced \u2014 either way an oops (full panic with `panic_on_oops`) that tears down the mount."
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-10-30T12:22:38.495Z",
            "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "shortName": "Linux"
          },
          "references": [
            {
              "url": "https://git.kernel.org/stable/c/fdc23a47be015fba915c4f9dfd43c65ad4829a35"
            },
            {
              "url": "https://git.kernel.org/stable/c/f23d5c6b7540ec9b1e73a8ea3b2ae9045248d728"
            },
            {
              "url": "https://git.kernel.org/stable/c/241e58de23e7c1bbb9bee526c17d9a0f2a90fbad"
            },
            {
              "url": "https://git.kernel.org/stable/c/581fb78e0388b78911b0c920e4073737090c8b5f"
            },
            {
              "url": "https://git.kernel.org/stable/c/f57e53ea252363234f86674db475839e5b87102e"
            }
          ],
          "title": "smb: client: let recv_done verify data_offset, data_length and remaining_data_length",
          "x_generator": {
            "engine": "bippy-1.2.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "assignerShortName": "Linux",
        "cveId": "CVE-2025-39933",
        "datePublished": "2025-10-04T07:30:57.496Z",
        "dateReserved": "2025-04-16T07:20:57.148Z",
        "dateUpdated": "2026-10-30T12:22:38.495Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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