CVE-2026-68098 (GCVE-0-2026-68098)

Vulnerability from cvelistv5 – Published: 2026-08-10 11:58 – Updated: 2026-08-13 22:39
VLAI
Title
ksmbd: bound DACL dedup walk to copied ACEs
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: bound DACL dedup walk to copied ACEs set_ntacl_dacl() can stop copying ACEs before consuming the full input DACL when size accounting overflows. When that happens, num_aces reflects only the ACEs that were actually copied into the output DACL, but set_posix_acl_entries_dacl() still receives nt_num_aces and uses it to walk the existing ACE array during dedup. That makes the dedup walk scan past the copied ACE array and inspect buffer tail that does not contain valid ACEs. Split the two meanings currently carried by the NT ACE count. Pass the number of copied NT ACEs to bound the dedup walk, and preserve the original "input DACL had NT ACEs" state separately for the Everyone/default ACL fallback. This keeps the dedup walk aligned with the ACEs that are actually present in the rebuilt DACL.
Severity
8.8 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < 6d9d7aa4a2c99c31acfa28921c30b684110cf66c (git)
Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < b057a851129c6a084e7e393b62ca3abf6c2660bc (git)
Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < f1eba60db813ec28732bf18b5f0a67ebac9c3100 (git)
Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < a0ebdaa79e10210d4e8ed9fe138e8f4d569719e3 (git)
Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < 58d97fcd0bf1aee694e244cc28635b9df95b543b (git)
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Linux Linux Affected: 5.15
Unaffected: 0 , < 5.15 (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-rc5 , ≤ * (original_commit_for_fix)
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{
  "containers": {
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      "affected": [
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          "product": "Linux",
          "programFiles": [
            "fs/smb/server/smbacl.c"
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          "programFiles": [
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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              "versionType": "semver"
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            {
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              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
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            {
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              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc5",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "5.15",
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: bound DACL dedup walk to copied ACEs\n\nset_ntacl_dacl() can stop copying ACEs before consuming the full input\nDACL when size accounting overflows.\n\nWhen that happens, num_aces reflects only the ACEs that were actually\ncopied into the output DACL, but set_posix_acl_entries_dacl() still\nreceives nt_num_aces and uses it to walk the existing ACE array during\ndedup.\n\nThat makes the dedup walk scan past the copied ACE array and inspect\nbuffer tail that does not contain valid ACEs.\n\nSplit the two meanings currently carried by the NT ACE count. Pass the\nnumber of copied NT ACEs to bound the dedup walk, and preserve the\noriginal \"input DACL had NT ACEs\" state separately for the\nEveryone/default ACL fallback.\n\nThis keeps the dedup walk aligned with the ACEs that are actually\npresent in the rebuilt DACL."
        }
      ],
      "metrics": [
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            "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"
          },
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              "lang": "en",
              "value": "AV:N - The flaw is in ksmbd\u0027s in-kernel SMB server (fs/smb/server/smbacl.c), triggered when a remote client sends SMB2 QUERY_INFO (security descriptor) over TCP/445; build_sec_desc() reads the attacker\u0027s stored NTACL xattr and calls set_ntacl_dacl().\nAC:L - An authenticated attacker fully controls the crafted DACL planted via SMB2 SET_INFO and can deterministically trigger partial ACE copy (size overflow) then QUERY_INFO; no race or victim-dependent state is required beyond a file with POSIX ACLs on an ACL-xattr-enabled share.\nPR:L - Exploitation requires a completed SMB2 session and tree connect; planting the malicious security.NTACL xattr needs FILE_WRITE_DAC via SMB2 SET_INFO, and triggering needs an open file handle for QUERY_INFO\u2014standard low-privileged share access, not host root.\nUI:N - The server processes the attacker\u0027s SMB2 SET_INFO and QUERY_INFO requests automatically in ksmbd worker threads; no separate local user or administrator action is required beyond normal server operation.\nS:U - Impact is confined to kernel heap memory corruption and ACL processing within the ksmbd server context; it does not cross VM, container, or IOMMU security boundaries.\nC:H - The dedup walk scans past copied ACEs into buffer tail without valid ACE structures, performing out-of-bounds reads including ntace-\u003esid.sub_auth[ntace-\u003esid.num_subauth-1] on attacker-influenced data; per kernel guidance OOB reads score High.\nI:H - Out-of-bounds kernel heap access during the unbounded ACE walk is a memory corruption primitive; incorrect dedup can also append extra ACEs to the rebuilt security descriptor, enabling integrity impact beyond a simple crash.\nA:H - Walking invalid ACE headers (e.g., zero size fields) can hang the dedup loop, and out-of-bounds reads of invalid sid fields can kernel oops/panic, denying SMB service on the affected host."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-13T22:39:30.094Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/6d9d7aa4a2c99c31acfa28921c30b684110cf66c"
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          "url": "https://git.kernel.org/stable/c/b057a851129c6a084e7e393b62ca3abf6c2660bc"
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          "url": "https://git.kernel.org/stable/c/f1eba60db813ec28732bf18b5f0a67ebac9c3100"
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          "url": "https://git.kernel.org/stable/c/a0ebdaa79e10210d4e8ed9fe138e8f4d569719e3"
        },
        {
          "url": "https://git.kernel.org/stable/c/58d97fcd0bf1aee694e244cc28635b9df95b543b"
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      ],
      "title": "ksmbd: bound DACL dedup walk to copied ACEs",
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-68098",
    "datePublished": "2026-08-10T11:58:12.768Z",
    "dateReserved": "2026-07-30T09:28:09.368Z",
    "dateUpdated": "2026-08-13T22:39:30.094Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
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      "date": "2026-08-14",
      "epss": "0.00414",
      "percentile": "0.34438"
    },
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-14T17:29:49+00:00",
      "cve": "CVE-2026-68098",
      "id": "CVE-2026-68098",
      "initial_release_date": "2026-08-10T00:00:00+00:00",
      "product_status:known_affected": "156",
      "product_status:known_not_affected": "120",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ksmbd: bound DACL dedup walk to copied ACEs",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-68098.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-11T23:48:28Z",
      "cve": "CVE-2026-68098",
      "id": "CVE-2026-68098",
      "initial_release_date": "2026-08-11T23:48:28Z",
      "product_status:known_affected": "113",
      "product_status:known_not_affected": "183",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-68098",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-68098.json",
      "version": "2"
    }
  }
}



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Sightings

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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.