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GHSA-JV66-Q3CR-4688

Vulnerability from github – Published: 2026-08-10 15:33 – Updated: 2026-08-19 18:32

Details

In the Linux kernel, the following vulnerability has been resolved:

smb: client: validate DFS referral PathConsumed

parse_dfs_referrals() validates that the response contains the fixed referral entry array and, on for-next, the per-referral string offsets. However, the response also contains a PathConsumed value that is later used for DFS path parsing.

If a malformed response provides a PathConsumed value larger than the search name, later DFS parsing can advance beyond the end of the path.

Validate PathConsumed against the search name length before storing it in the parsed referral.

Severity

9.1 (Critical)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-68343"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-10T13:20:24Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: validate DFS referral PathConsumed\n\nparse_dfs_referrals() validates that the response contains the fixed\nreferral entry array and, on for-next, the per-referral string offsets.\nHowever, the response also contains a PathConsumed value that is later\nused for DFS path parsing.\n\nIf a malformed response provides a PathConsumed value larger than the\nsearch name, later DFS parsing can advance beyond the end of the path.\n\nValidate PathConsumed against the search name length before storing it in\nthe parsed referral.",
  "id": "GHSA-jv66-q3cr-4688",
  "modified": "2026-08-19T18:32:15Z",
  "published": "2026-08-10T15:33:47Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-68343"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/285bd4a5f3f156aa5869843b47a1b1380b774241"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2fdd6d196c656b376cc251e1e9ff110b3ed522e1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5b439f39f33ec15d319ced3b025e122346fba987"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9f88a99ed511651b2dc2177d6854b2d1b8322e75"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bfebe5110fd135d86d65a0a346e14c106b02028b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f6f5ee2aa33b350c671721b965251c42cebb962e"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-68343 (GCVE-0-2026-68343)

Vulnerability from cvelistv5 – Published: 2026-08-10 12:03 – Updated: 2026-08-19 16:33

Title

smb: client: validate DFS referral PathConsumed

Summary

In the Linux kernel, the following vulnerability has been resolved: smb: client: validate DFS referral PathConsumed parse_dfs_referrals() validates that the response contains the fixed referral entry array and, on for-next, the per-referral string offsets. However, the response also contains a PathConsumed value that is later used for DFS path parsing. If a malformed response provides a PathConsumed value larger than the search name, later DFS parsing can advance beyond the end of the path. Validate PathConsumed against the search name length before storing it in the parsed referral.

Severity

9.1 (Critical)


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

Assigner

Linux mitre root

References

6 references

URL	Tags
https://git.kernel.org/stable/c/bfebe5110fd135d86…
https://git.kernel.org/stable/c/5b439f39f33ec15d3…
https://git.kernel.org/stable/c/285bd4a5f3f156aa5…
https://git.kernel.org/stable/c/2fdd6d196c656b376…
https://git.kernel.org/stable/c/9f88a99ed511651b2…
https://git.kernel.org/stable/c/f6f5ee2aa33b350c6…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 4ecce920e13ace16a5ba45efe8909946c28fb2ad , < bfebe5110fd135d86d65a0a346e14c106b02028b (git) Affected: 4ecce920e13ace16a5ba45efe8909946c28fb2ad , < 5b439f39f33ec15d319ced3b025e122346fba987 (git) Affected: 4ecce920e13ace16a5ba45efe8909946c28fb2ad , < 285bd4a5f3f156aa5869843b47a1b1380b774241 (git) Affected: 4ecce920e13ace16a5ba45efe8909946c28fb2ad , < 2fdd6d196c656b376cc251e1e9ff110b3ed522e1 (git) Affected: 4ecce920e13ace16a5ba45efe8909946c28fb2ad , < 9f88a99ed511651b2dc2177d6854b2d1b8322e75 (git) Affected: 4ecce920e13ace16a5ba45efe8909946c28fb2ad , < f6f5ee2aa33b350c671721b965251c42cebb962e (git)
Linux	Linux	Affected: 4.11 Unaffected: 0 , < 4.11 (semver) Unaffected: 6.1.183 , ≤ 6.1.* (semver) Unaffected: 6.6.148 , ≤ 6.6.* (semver) Unaffected: 6.12.101 , ≤ 6.12.* (semver) Unaffected: 6.18.42 , ≤ 6.18.* (semver) Unaffected: 7.1.6 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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{
  "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": "bfebe5110fd135d86d65a0a346e14c106b02028b",
              "status": "affected",
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              "versionType": "git"
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              "version": "4ecce920e13ace16a5ba45efe8909946c28fb2ad",
              "versionType": "git"
            },
            {
              "lessThan": "9f88a99ed511651b2dc2177d6854b2d1b8322e75",
              "status": "affected",
              "version": "4ecce920e13ace16a5ba45efe8909946c28fb2ad",
              "versionType": "git"
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              "status": "affected",
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              "versionType": "git"
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          "versions": [
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              "version": "4.11"
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "6.6.148",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.101",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
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        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.183",
                  "versionStartIncluding": "4.11",
                  "vulnerable": true
                },
                {
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                  "versionStartIncluding": "4.11",
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                {
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              "operator": "OR"
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        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: validate DFS referral PathConsumed\n\nparse_dfs_referrals() validates that the response contains the fixed\nreferral entry array and, on for-next, the per-referral string offsets.\nHowever, the response also contains a PathConsumed value that is later\nused for DFS path parsing.\n\nIf a malformed response provides a PathConsumed value larger than the\nsearch name, later DFS parsing can advance beyond the end of the path.\n\nValidate PathConsumed against the search name length before storing it in\nthe parsed referral."
        }
      ],
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            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
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          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The tainted PathConsumed value comes directly from a GET_DFS_REFERRAL response received over TCP/445 from the SMB server, so a malicious or MITM-positioned server on the network fully controls the input to the vulnerable code.\nAC:L - The server simply sets an oversized PathConsumed (up to 65535, and it can also clear the SMB1 UNICODE flag to select the completely unvalidated branch); the resulting out-of-bounds walk past the path buffer is deterministic and needs no race or memory-layout luck.\nPR:N - The attacker is the remote server (or a MITM on an unsigned connection) and needs no account or privilege on the victim client; the client parses the referral response as part of establishing the connection.\nUI:N - DFS referral walks are performed automatically by autofs/systemd automounts, fstab mounts at boot and reconnect-driven remounts, so a forged referral can be delivered without any user action.\nS:U - The out-of-bounds access stays within the kernel\u0027s own memory and mount context on the client; no VM, IOMMU or sandbox boundary is crossed.\nC:H - prepath = full_path + path_consumed points past the end of the heap path string, and cifs_build_devname() strlen()s and copies from there, splicing adjacent kernel heap contents (up to ~64KB away) into the constructed UNC/prefixpath that is then observable via the mount source and /proc/mounts.\nI:N - The defect is purely an out-of-bounds read; all subsequent allocations and copies are sized from the same over-read string, so no kernel memory is written or corrupted.\nA:H - With PathConsumed up to 65535 the pointer can run far past a small slab object into an unmapped or guarded page, so strlen() on it oopses the mounting task (and panics on panic_on_oops systems)."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-19T16:33:43.025Z",
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        },
        {
          "url": "https://git.kernel.org/stable/c/9f88a99ed511651b2dc2177d6854b2d1b8322e75"
        },
        {
          "url": "https://git.kernel.org/stable/c/f6f5ee2aa33b350c671721b965251c42cebb962e"
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      ],
      "title": "smb: client: validate DFS referral PathConsumed",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-68343",
    "datePublished": "2026-08-10T12:03:19.939Z",
    "dateReserved": "2026-07-30T09:28:09.384Z",
    "dateUpdated": "2026-08-19T16:33:43.025Z",
    "state": "PUBLISHED"
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  "dataType": "CVE_RECORD",
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}

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.

Detection rules are retrieved from Rulezet.

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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