CVE-2025-37899 (GCVE-0-2025-37899)
Vulnerability from cvelistv5
Published
2025-05-20 15:21
Modified
2026-08-05 11:58
Severity ?
8.8 (High) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in session logoff The sess->user object can currently be in use by another thread, for example if another connection has sent a session setup request to bind to the session being free'd. The handler for that connection could be in the smb2_sess_setup function which makes use of sess->user.
References
Impacted products
Vendor Product Version
Linux Linux Version: 0626e6641f6b467447c81dd7678a69c66f7746cf
Version: 0626e6641f6b467447c81dd7678a69c66f7746cf
Version: 0626e6641f6b467447c81dd7678a69c66f7746cf
Version: 0626e6641f6b467447c81dd7678a69c66f7746cf
Version: 0626e6641f6b467447c81dd7678a69c66f7746cf
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2025-05-24T19:05:08.356Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "https://sean.heelan.io/2025/05/22/how-i-used-o3-to-find-cve-2025-37899-a-remote-zeroday-vulnerability-in-the-linux-kernels-smb-implementation/"
          },
          {
            "url": "https://news.ycombinator.com/item?id=44081338"
          }
        ],
        "title": "CVE Program Container",
        "x_generator": {
          "engine": "ADPogram 0.0.1"
        }
      }
    ],
    "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": "931dc8a3670f71c45c0b1379ea4e92dafbda1aca",
              "status": "affected",
              "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
              "versionType": "git"
            },
            {
              "lessThan": "70ad6455139e26e85f48f95d0e21f351c1909342",
              "status": "affected",
              "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
              "versionType": "git"
            },
            {
              "lessThan": "d5ec1d79509b3ee01de02c236f096bc050221b7f",
              "status": "affected",
              "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
              "versionType": "git"
            },
            {
              "lessThan": "02d16046cd11a5c037b28c12ffb818c56dd3ef43",
              "status": "affected",
              "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
              "versionType": "git"
            },
            {
              "lessThan": "2fc9feff45d92a92cd5f96487655d5be23fb7e2b",
              "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": "6.1.*",
              "status": "unaffected",
              "version": "6.1.159",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.119",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.28",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.14.*",
              "status": "unaffected",
              "version": "6.14.6",
              "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": "6.1.159",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.119",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.28",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.14.6",
                  "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: fix use-after-free in session logoff\n\nThe sess-\u003euser object can currently be in use by another thread, for\nexample if another connection has sent a session setup request to\nbind to the session being free\u0027d. The handler for that connection could\nbe in the smb2_sess_setup function which makes use of sess-\u003euser."
        }
      ],
      "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; both the freeing SMB2 LOGOFF and the racing SMB2 SESSION_SETUP (multichannel bind) are ordinary SMB PDUs delivered over TCP/445 from a remote client. No local access is required.\nAC:L - The attacker controls both sides of the race \u2014 they open both TCP connections and choose when to send LOGOFF and the binding SESSION_SETUP \u2014 and both paths block on slow ksmbd.mountd IPC round trips (`ksmbd_ipc_login_request()` / `ksmbd_ipc_logout_request()`), giving a very wide window that can be retried indefinitely with fresh sessions.\nPR:L - `smb2_session_logoff()` is gated by `ksmbd_conn_good()` and a successful `ksmbd_session_lookup_all()`, and channel binding requires a non-guest session, so the attacker needs one ordinary unprivileged SMB account (any share user, no admin rights) \u2014 matching the kernel CNA scoring of the sibling multichannel session UAFs CVE-2025-22040/22041.\nUI:N - The attacker drives both connections and both SMB requests entirely on their own; no action by any local user or administrator is needed.\nS:U - The corruption stays within the kernel\u0027s own memory and security authority \u2014 a standard in-kernel use-after-free with no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - The freed `struct ksmbd_user` holds `name`, `passkey` and `passkey_sz`; after reclaim, `ksmbd_compare_user()` performs a `memcmp` of attacker-chosen length through a dangling pointer (unbounded OOB read usable as an oracle) and `smb2_query_info` FS_OBJECTID copies 16 bytes via `user_passkey(sess-\u003euser)` straight into the network response, disclosing kernel memory and the victim\u0027s NTLM passkey to the remote client.\nI:H - `set_user_flag(sess-\u003euser, KSMBD_USER_FLAG_BAD_PASSWORD)` performs an OR-write into the freed object, and `sess-\u003euser-\u003euid`/`-\u003egid` from freed memory drive `smb_inherit_dacl()` and file ownership; combined with heap spraying of the reclaimed slab object this yields a write primitive suitable for control-flow hijack.\nA:H - Dereferencing the freed `ksmbd_user` (and the `sess-\u003euser = NULL` store racing other readers) reliably produces kernel oopses, slab corruption, or a panic, taking down the file server."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T11:58:10.107Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/931dc8a3670f71c45c0b1379ea4e92dafbda1aca"
        },
        {
          "url": "https://git.kernel.org/stable/c/70ad6455139e26e85f48f95d0e21f351c1909342"
        },
        {
          "url": "https://git.kernel.org/stable/c/d5ec1d79509b3ee01de02c236f096bc050221b7f"
        },
        {
          "url": "https://git.kernel.org/stable/c/02d16046cd11a5c037b28c12ffb818c56dd3ef43"
        },
        {
          "url": "https://git.kernel.org/stable/c/2fc9feff45d92a92cd5f96487655d5be23fb7e2b"
        }
      ],
      "title": "ksmbd: fix use-after-free in session logoff",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-37899",
    "datePublished": "2025-05-20T15:21:34.782Z",
    "dateReserved": "2025-04-16T04:51:23.965Z",
    "dateUpdated": "2026-08-05T11:58:10.107Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.