Vulnerability-Lookup

FKIE_CVE-2026-97562

Vulnerability from fkie_nvd - Published: 2026-09-25 11:17 - Updated: 2026-09-25 15:17

Severity

7.5 (High) - CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: smb: client: pin DFS superblock in iterator callback tcon_super_cb() stores a raw superblock pointer, but __cifs_get_super() takes its active reference only after iterate_supers_type() has dropped s_umount and its passive reference. Concurrent DFS automount expiry can therefore free the superblock before cifs_sb_active() uses it. A deterministic KASAN test reproduces the race as: BUG: KASAN: slab-use-after-free in cifs_sb_active+0x77/0x80 The same test passes with this change applied. Take the active reference in the callback while iterate_supers_type() still holds s_umount shared. cifs_put_tcp_super() remains the matching release.

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/5b01a8c0209690db75341528ec53fd87e0ac1460
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/a6b6561522212af852c9ad8a7dca8d59ef2c7377
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/d806d5a85dcbe2a0f181b2f0f9f61ddfbefa1818
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/ea43a15cea36dc5ddd832be5bddeac7dd804cbcf

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/misc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ea43a15cea36dc5ddd832be5bddeac7dd804cbcf",
              "status": "affected",
              "version": "bacd704a95ad0b93af995aae4a523aa046f46563",
              "versionType": "git"
            },
            {
              "lessThan": "a6b6561522212af852c9ad8a7dca8d59ef2c7377",
              "status": "affected",
              "version": "bacd704a95ad0b93af995aae4a523aa046f46563",
              "versionType": "git"
            },
            {
              "lessThan": "5b01a8c0209690db75341528ec53fd87e0ac1460",
              "status": "affected",
              "version": "bacd704a95ad0b93af995aae4a523aa046f46563",
              "versionType": "git"
            },
            {
              "lessThan": "d806d5a85dcbe2a0f181b2f0f9f61ddfbefa1818",
              "status": "affected",
              "version": "bacd704a95ad0b93af995aae4a523aa046f46563",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/misc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.7"
            },
            {
              "lessThan": "5.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: pin DFS superblock in iterator callback\n\ntcon_super_cb() stores a raw superblock pointer, but __cifs_get_super()\ntakes its active reference only after iterate_supers_type() has dropped\ns_umount and its passive reference. Concurrent DFS automount expiry can\ntherefore free the superblock before cifs_sb_active() uses it.\n\nA deterministic KASAN test reproduces the race as:\n\n  BUG: KASAN: slab-use-after-free in cifs_sb_active+0x77/0x80\n\nThe same test passes with this change applied.\n\nTake the active reference in the callback while iterate_supers_type()\nstill holds s_umount shared. cifs_put_tcp_super() remains the matching\nrelease."
    }
  ],
  "id": "CVE-2026-97562",
  "lastModified": "2026-09-25T15:17:59.183",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.6,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-25T11:17:06.757",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5b01a8c0209690db75341528ec53fd87e0ac1460"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a6b6561522212af852c9ad8a7dca8d59ef2c7377"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d806d5a85dcbe2a0f181b2f0f9f61ddfbefa1818"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ea43a15cea36dc5ddd832be5bddeac7dd804cbcf"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

CVE-2026-97562 (GCVE-0-2026-97562)

Vulnerability from cvelistv5 – Published: 2026-09-25 10:21 – Updated: 2026-09-25 14:41

Title

smb: client: pin DFS superblock in iterator callback

Summary

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

4 references

URL	Tags
https://git.kernel.org/stable/c/ea43a15cea36dc5dd…
https://git.kernel.org/stable/c/a6b6561522212af85…
https://git.kernel.org/stable/c/5b01a8c0209690db7…
https://git.kernel.org/stable/c/d806d5a85dcbe2a0f…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: bacd704a95ad0b93af995aae4a523aa046f46563 , < ea43a15cea36dc5ddd832be5bddeac7dd804cbcf (git) Affected: bacd704a95ad0b93af995aae4a523aa046f46563 , < a6b6561522212af852c9ad8a7dca8d59ef2c7377 (git) Affected: bacd704a95ad0b93af995aae4a523aa046f46563 , < 5b01a8c0209690db75341528ec53fd87e0ac1460 (git) Affected: bacd704a95ad0b93af995aae4a523aa046f46563 , < d806d5a85dcbe2a0f181b2f0f9f61ddfbefa1818 (git)
Linux	Linux	Affected: 5.7 Unaffected: 0 , < 5.7 (semver) Unaffected: 6.12.111 , ≤ 6.12.* (semver) Unaffected: 6.18.53 , ≤ 6.18.* (semver) Unaffected: 7.2.7 , ≤ 7.2.* (semver) Unaffected: 7.3-rc3 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/misc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ea43a15cea36dc5ddd832be5bddeac7dd804cbcf",
              "status": "affected",
              "version": "bacd704a95ad0b93af995aae4a523aa046f46563",
              "versionType": "git"
            },
            {
              "lessThan": "a6b6561522212af852c9ad8a7dca8d59ef2c7377",
              "status": "affected",
              "version": "bacd704a95ad0b93af995aae4a523aa046f46563",
              "versionType": "git"
            },
            {
              "lessThan": "5b01a8c0209690db75341528ec53fd87e0ac1460",
              "status": "affected",
              "version": "bacd704a95ad0b93af995aae4a523aa046f46563",
              "versionType": "git"
            },
            {
              "lessThan": "d806d5a85dcbe2a0f181b2f0f9f61ddfbefa1818",
              "status": "affected",
              "version": "bacd704a95ad0b93af995aae4a523aa046f46563",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/misc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.7"
            },
            {
              "lessThan": "5.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.111",
                  "versionStartIncluding": "5.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.53",
                  "versionStartIncluding": "5.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.7",
                  "versionStartIncluding": "5.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc3",
                  "versionStartIncluding": "5.7",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: pin DFS superblock in iterator callback\n\ntcon_super_cb() stores a raw superblock pointer, but __cifs_get_super()\ntakes its active reference only after iterate_supers_type() has dropped\ns_umount and its passive reference. Concurrent DFS automount expiry can\ntherefore free the superblock before cifs_sb_active() uses it.\n\nA deterministic KASAN test reproduces the race as:\n\n  BUG: KASAN: slab-use-after-free in cifs_sb_active+0x77/0x80\n\nThe same test passes with this change applied.\n\nTake the active reference in the callback while iterate_supers_type()\nstill holds s_umount shared. cifs_put_tcp_super() remains the matching\nrelease."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The racing side is started by the remote SMB server: dropping the session or replying STATUS_NETWORK_NAME_DELETED makes the client run smb2_reconnect() -\u003e cifs_tree_connect() -\u003e cifs_get_dfs_tcon_super() -\u003e __cifs_get_super(). There, tcon_super_cb() saves a raw superblock pointer that is used after s_umount is released.\nAC:H - The server can force reconnects repeatedly, but the superblock is only freed if a DFS-link automount expires via cifs_expire_automounts() (a 500s periodic timer, idle submount only) inside the small gap between iterate_supers_type() returning and cifs_sb_active(). The attacker does not control that timing.\nPR:N - The attacker is the SMB/DFS server or a network peer that can reset the client\u0027s session. Forcing the client\u0027s tree reconnect needs no account or privilege on the client.\nUI:R - A victim must have mounted a DFS share with an automounted DFS link from the attacker-reachable server (cifs mounts need real CAP_SYS_ADMIN, not a user namespace), and the link must be idle long enough to expire.\nS:U - The use-after-free corrupts memory in the same kernel that runs the CIFS client, so no separate security authority is crossed.\nC:H - After the freed super_block and cifs_sb_info are reused, the reconnect path keeps reading them (cifs_sb_active() on freed memory, then CIFS_SB(sb) fields in tree_connect_dfs_target()), so reclaimed slab contents can be read.\nI:H - cifs_sb_active() increments counters in the freed cifs_sb/sb, and cifs_update_super_prepath() frees and replaces cifs_sb-\u003eprepath in the freed cifs_sb_info. Both are writes into freed memory that can be turned into heap corruption.\nA:H - The fix commit reports a KASAN slab-use-after-free in cifs_sb_active(); without KASAN the corrupted superblock refcounts and the later cifs_put_tcp_super()/deactivate_super() can crash the kernel."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-25T14:41:15.022Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ea43a15cea36dc5ddd832be5bddeac7dd804cbcf"
        },
        {
          "url": "https://git.kernel.org/stable/c/a6b6561522212af852c9ad8a7dca8d59ef2c7377"
        },
        {
          "url": "https://git.kernel.org/stable/c/5b01a8c0209690db75341528ec53fd87e0ac1460"
        },
        {
          "url": "https://git.kernel.org/stable/c/d806d5a85dcbe2a0f181b2f0f9f61ddfbefa1818"
        }
      ],
      "title": "smb: client: pin DFS superblock in iterator callback",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-97562",
    "datePublished": "2026-09-25T10:21:50.664Z",
    "dateReserved": "2026-09-24T16:01:01.155Z",
    "dateUpdated": "2026-09-25T14:41:15.022Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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FKIE_CVE-2026-97562

CVE-2026-97562 (GCVE-0-2026-97562)

Tags

Sightings

Nomenclature

Related by attack behaviour