libsmb2 — security advisory

{
  "id": "1e57ce824d095cc585d4b40c2bcf7491f681143bbdf241288f22ee4f4e5af8b3",
  "url": "https://osv.dev/vulnerability/UBUNTU-CVE-2025-57632",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "UBUNTU-CVE-2025-57632",
    "summary": "libsmb2 6.2+ is vulnerable to Buffer Overflow. When processing SMB2 chained PDUs (NextCommand), libsmb2 repeatedly calls smb2_add_iovector() to append to a fixed-size iovec array without checking the upper bound of v->niov (SMB2_MAX_VECTORS=256). An attacker can craft responses with many chained PDUs to overflow v->niov and perform heap out-of-bounds writes, causing memory corruption, crashes, and potentially arbitrary code execution. The SMB2_OPLOCK_BREAK path bypasses message ID validation.",
    "evidence": "osv:UBUNTU-CVE-2025-57632",
    "products": [
      {
        "name": {
          "value": "libsmb2",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "6.2+dfsg-2",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "libsmb2",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "6.2+dfsg-3",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "6.2+dfsg-4",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "libsmb2",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "6.2+dfsg-2",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "6.2+dfsg-3",
            "evidence": "/affected/2/versions"
          }
        ]
      }
    ],
    "severity": "high",
    "structured": {
      "id": "UBUNTU-CVE-2025-57632",
      "aliases": [
        "UBUNTU-CVE-2025-57632"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        },
        {
          "type": "Ubuntu",
          "score": "medium"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "libsmb2",
            "purl": "pkg:deb/ubuntu/libsmb2?arch=source&distro=questing",
            "ecosystem": "Ubuntu:25.10"
          },
          "versions": [
            "6.2+dfsg-2"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-57632.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "libsmb2-6",
                "binary_version": "6.2+dfsg-2"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "libsmb2",
            "purl": "pkg:deb/ubuntu/libsmb2?arch=source&distro=stonking",
            "ecosystem": "Ubuntu:26.10"
          },
          "versions": [
            "6.2+dfsg-3",
            "6.2+dfsg-4"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-57632.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "libsmb2-6",
                "binary_version": "6.2+dfsg-4"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "libsmb2",
            "purl": "pkg:deb/ubuntu/libsmb2?arch=source&distro=resolute",
            "ecosystem": "Ubuntu:26.04:LTS"
          },
          "versions": [
            "6.2+dfsg-2",
            "6.2+dfsg-3"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-57632.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "libsmb2-6",
                "binary_version": "6.2+dfsg-3"
              }
            ]
          }
        }
      ],
      "modified": "2026-10-17T12:57:09.082853178Z",
      "provider": "osv",
      "upstream": [
        "CVE-2025-57632"
      ],
      "references": [
        "https://ubuntu.com/security/CVE-2025-57632",
        "https://www.cve.org/CVERecord?id=CVE-2025-57632",
        "https://gist.github.com/ZjW1nd/0b95b63307ceee7890e88e4abc6f041e",
        "https://github.com/sahlberg/libsmb2",
        "https://github.com/sahlberg/libsmb2/blob/master/lib/compat.c#L569"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2025-57632",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 356799,
  "published_at": "2025-09-25T20:15:00+00:00"
}