Vulnerability-Lookup

FKIE_CVE-2026-43215

Vulnerability from fkie_nvd - Published: 2026-05-06 12:16 - Updated: 2026-06-17 10:49

Severity

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

Summary

In the Linux kernel, the following vulnerability has been resolved: cifs: Fix locking usage for tcon fields We used to use the cifs_tcp_ses_lock to protect a lot of objects that are not just the server, ses or tcon lists. We later introduced srv_lock, ses_lock and tc_lock to protect fields within the corresponding structs. This was done to provide a more granular protection and avoid unnecessary serialization. There were still a couple of uses of cifs_tcp_ses_lock to provide tcon fields. In this patch, I've replaced them with tc_lock.

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/3969db6b22e3d90d8c5f22ac1a7fe0350a94c136	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/601dd3b79769b38d30b693c40afdb2a4b7edf9d0	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/8c59eeeeffa1524ef57e173a89a1a3ff539888d5	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/953953abb66e52c224057ab91e404284fefeab62	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/96c4af418586ee9a6aab61738644366426e05316	Patch

Impacted products

Vendor	Product	Version
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/cached_dir.c",
            "fs/smb/client/smb2misc.c",
            "fs/smb/client/smb2ops.c",
            "fs/smb/client/smb2pdu.c",
            "fs/smb/client/trace.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
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              "status": "affected",
              "version": "d7d7a66aacd6fd8ca57baf08a7bac5421282f6f8",
              "versionType": "git"
            },
            {
              "lessThan": "601dd3b79769b38d30b693c40afdb2a4b7edf9d0",
              "status": "affected",
              "version": "d7d7a66aacd6fd8ca57baf08a7bac5421282f6f8",
              "versionType": "git"
            },
            {
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              "version": "d7d7a66aacd6fd8ca57baf08a7bac5421282f6f8",
              "versionType": "git"
            },
            {
              "lessThan": "8c59eeeeffa1524ef57e173a89a1a3ff539888d5",
              "status": "affected",
              "version": "d7d7a66aacd6fd8ca57baf08a7bac5421282f6f8",
              "versionType": "git"
            },
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              "status": "affected",
              "version": "d7d7a66aacd6fd8ca57baf08a7bac5421282f6f8",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
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            "fs/smb/client/smb2misc.c",
            "fs/smb/client/smb2ops.c",
            "fs/smb/client/smb2pdu.c",
            "fs/smb/client/trace.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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            },
            {
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "6.12.75",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.16",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "6FE38AB6-B81E-42D1-8F9E-C6AE1F58C425",
              "versionEndExcluding": "6.6.128",
              "versionStartIncluding": "6.0",
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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncifs: Fix locking usage for tcon fields\n\nWe used to use the cifs_tcp_ses_lock to protect a lot of objects\nthat are not just the server, ses or tcon lists. We later introduced\nsrv_lock, ses_lock and tc_lock to protect fields within the\ncorresponding structs. This was done to provide a more granular\nprotection and avoid unnecessary serialization.\n\nThere were still a couple of uses of cifs_tcp_ses_lock to provide\ntcon fields. In this patch, I\u0027ve replaced them with tc_lock."
    }
  ],
  "id": "CVE-2026-43215",
  "lastModified": "2026-06-17T10:49:10.173",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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"
      }
    ]
  },
  "published": "2026-05-06T12:16:41.063",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/3969db6b22e3d90d8c5f22ac1a7fe0350a94c136"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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    },
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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    },
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      "tags": [
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    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/96c4af418586ee9a6aab61738644366426e05316"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-667"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}

CVE-2026-43215 (GCVE-0-2026-43215)

Vulnerability from cvelistv5 – Published: 2026-05-06 11:28 – Updated: 2026-08-05 12:26

Title

cifs: Fix locking usage for tcon fields

Summary

Severity

8.8 (High)


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

Assigner

Linux mitre root Scorecard

References

5 references

URL	Tags
https://git.kernel.org/stable/c/953953abb66e52c22…
https://git.kernel.org/stable/c/601dd3b79769b38d3…
https://git.kernel.org/stable/c/3969db6b22e3d90d8…
https://git.kernel.org/stable/c/8c59eeeeffa1524ef…
https://git.kernel.org/stable/c/96c4af418586ee9a6…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: d7d7a66aacd6fd8ca57baf08a7bac5421282f6f8 , < 953953abb66e52c224057ab91e404284fefeab62 (git) Affected: d7d7a66aacd6fd8ca57baf08a7bac5421282f6f8 , < 601dd3b79769b38d30b693c40afdb2a4b7edf9d0 (git) Affected: d7d7a66aacd6fd8ca57baf08a7bac5421282f6f8 , < 3969db6b22e3d90d8c5f22ac1a7fe0350a94c136 (git) Affected: d7d7a66aacd6fd8ca57baf08a7bac5421282f6f8 , < 8c59eeeeffa1524ef57e173a89a1a3ff539888d5 (git) Affected: d7d7a66aacd6fd8ca57baf08a7bac5421282f6f8 , < 96c4af418586ee9a6aab61738644366426e05316 (git)
Linux	Linux	Affected: 6.0 Unaffected: 0 , < 6.0 (semver) Unaffected: 6.6.128 , ≤ 6.6.* (semver) Unaffected: 6.12.75 , ≤ 6.12.* (semver) Unaffected: 6.18.16 , ≤ 6.18.* (semver) Unaffected: 6.19.6 , ≤ 6.19.* (semver) Unaffected: 7.0 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/cached_dir.c",
            "fs/smb/client/smb2misc.c",
            "fs/smb/client/smb2ops.c",
            "fs/smb/client/smb2pdu.c",
            "fs/smb/client/trace.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
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              "status": "affected",
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              "versionType": "git"
            },
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              "version": "d7d7a66aacd6fd8ca57baf08a7bac5421282f6f8",
              "versionType": "git"
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              "versionType": "git"
            },
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            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
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            "fs/smb/client/smb2misc.c",
            "fs/smb/client/smb2ops.c",
            "fs/smb/client/smb2pdu.c",
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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              "versionType": "semver"
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              "version": "6.12.75",
              "versionType": "semver"
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              "status": "unaffected",
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            },
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              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.6",
              "versionType": "semver"
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              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
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      "cpeApplicability": [
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                },
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        }
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            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The vulnerable CIFS/SMB client code is exercised through SMB protocol activity with a remote server, including DFS referral handling, reconnects, cancelled closes, and cached directory lease cleanup. A malicious or compromised SMB server can influence these network-driven paths after a client connects.\nAC:L - The issue is a locking/refcount race, but the remote SMB peer can repeatedly trigger reconnects, delayed/cancelled responses, DFS behavior, and lease/cached-directory activity to exercise the affected paths. There is no rare configuration or uncontrollable one-shot condition required beyond a CIFS mount being in use.\nPR:N - The attacker does not need privileges on the vulnerable client system; they can act as the SMB server or network peer providing crafted behavior to the CIFS client. Although mounting CIFS locally is privileged, that is victim-side setup/user interaction rather than attacker privileges on the impacted host.\nUI:R - Exploitation requires the client system to mount or otherwise use an SMB/CIFS share, which is a victim/user or administrator action. Once connected, the malicious server can drive the vulnerable network paths.\nS:U - The impact is within the same Linux kernel security authority running the CIFS client. This is standard kernel memory corruption/panic potential, not a VM escape or cross-authority boundary bypass.\nC:H - The inconsistent locking can corrupt the tcon reference count and allow use-after-free of `struct cifs_tcon`. Kernel UAF conditions are reasonably capable of being shaped into memory disclosure primitives.\nI:H - The same premature free and later dereference/use of the tcon object creates kernel heap use-after-free memory corruption. Under the required higher-severity rule, this is treated as potentially exploitable for arbitrary write or control-flow compromise.\nA:H - At minimum, refcount corruption and use-after-free of a live CIFS tcon can lead to kernel oops, panic, or hangs in reconnect/close/DFS workqueue paths. The condition can be triggered repeatedly by malicious SMB server behavior while the share is mounted."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:26:40.744Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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        },
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        },
        {
          "url": "https://git.kernel.org/stable/c/96c4af418586ee9a6aab61738644366426e05316"
        }
      ],
      "title": "cifs: Fix locking usage for tcon fields",
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        "engine": "bippy-1.2.0"
      }
    }
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43215",
    "datePublished": "2026-05-06T11:28:17.425Z",
    "dateReserved": "2026-05-01T14:12:55.993Z",
    "dateUpdated": "2026-08-05T12:26:40.744Z",
    "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-2026-43215

CVE-2026-43215 (GCVE-0-2026-43215)

Tags

Sightings

Nomenclature

Related by attack behaviour