CVE-2026-98636 (GCVE-0-2026-98636)

Vulnerability from cvelistv5 – Published: 2026-10-18 15:20 – Updated: 2026-10-19 09:23
VLAI
Title
squashfs: Add dictionary size range check to prevent shift-out-of-bounds
Summary
In the Linux kernel, the following vulnerability has been resolved: squashfs: Add dictionary size range check to prevent shift-out-of-bounds When an abnormal SquashFS image (COMP_OPTS flag is 1 but dictionary size is 0) is mounted, and performs shift operations using dictionarysize, the shift exponent is -1, causing a shift-out-of-bounds. Detail as below: squashfs_comp_opts(msblk, buffer, length) squashfs_xz_comp_opts() if (comp_opts) n = ffs(opts->dict_size) - 1;<----opts->dict_size=0, n=-1 if (opts->dict_size != (1 << n) && opts->dict_size != (1 << n) + (1 << (n + 1))) <----shift-out-of-bounds Fix it by adding a dictionary size range check before the shift operation.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6820 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: ff750311d30acc9564ef577050794953eee59f01 , < b02948a23455f8190a53887b2d2c13ae1d360cea (git)
Affected: ff750311d30acc9564ef577050794953eee59f01 , < 9d9c5c218ea356a1d88765214ad2919605280ab1 (git)
Affected: ff750311d30acc9564ef577050794953eee59f01 , < 7a1c293e7aa17f1afaee0684e0e931fe23a5a6b1 (git)
Affected: ff750311d30acc9564ef577050794953eee59f01 , < c68e0068a236f9a7dfc19720bdf11e5d80a85089 (git)
Affected: ff750311d30acc9564ef577050794953eee59f01 , < 88c673a0bd233df44ca0020da82f4fd3876de27a (git)
Affected: ff750311d30acc9564ef577050794953eee59f01 , < 0cb85377daaefb4ce5ce72975f2deb27ee0e0cad (git)
Affected: ff750311d30acc9564ef577050794953eee59f01 , < e1ca4e3a380ef3e8f46ce006f1146392e3f32c98 (git)
Affected: ff750311d30acc9564ef577050794953eee59f01 , < 1f7745fb3580152ca902ef181b605f33cabfb1d0 (git)
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Linux Linux Affected: 2.6.39
Unaffected: 0 , < 2.6.39 (semver)
Unaffected: 5.10.271 , ≤ 5.10.* (semver)
Unaffected: 5.15.222 , ≤ 5.15.* (semver)
Unaffected: 6.1.189 , ≤ 6.1.* (semver)
Unaffected: 6.6.158 , ≤ 6.6.* (semver)
Unaffected: 6.12.112 , ≤ 6.12.* (semver)
Unaffected: 6.18.55 , ≤ 6.18.* (semver)
Unaffected: 7.2.9 , ≤ 7.2.* (semver)
Unaffected: 7.3 , ≤ * (original_commit_for_fix)
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsquashfs: Add dictionary size range check to prevent shift-out-of-bounds\n\nWhen an abnormal SquashFS image (COMP_OPTS flag is 1 but dictionary size\nis 0) is mounted, and performs shift operations using dictionarysize, the\nshift exponent is -1, causing a shift-out-of-bounds.\n\nDetail as below:\nsquashfs_comp_opts(msblk, buffer, length)\n  squashfs_xz_comp_opts()\n    if (comp_opts)\n      n = ffs(opts-\u003edict_size) - 1;\u003c----opts-\u003edict_size=0, n=-1\n      if (opts-\u003edict_size != (1 \u003c\u003c n) \u0026\u0026 opts-\u003edict_size !=\n\t  \t(1 \u003c\u003c n) + (1 \u003c\u003c (n + 1))) \u003c----shift-out-of-bounds\n\nFix it by adding a dictionary size range check before the shift operation."
        }
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      "providerMetadata": {
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        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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    "datePublished": "2026-10-18T15:20:07.184Z",
    "dateReserved": "2026-09-25T10:25:14.361Z",
    "dateUpdated": "2026-10-19T09:23:06.005Z",
    "state": "PUBLISHED"
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          }
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        "id": "CVE-2026-98636",
        "lastModified": "2026-10-19T10:19:27.837",
        "metrics": {},
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        "vulnStatus": "Received"
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      "current_release_date": "2026-10-29T08:20:03+00:00",
      "cve": "CVE-2026-98636",
      "id": "CVE-2026-98636",
      "initial_release_date": "2026-10-18T00:00:00+00:00",
      "product_status:known_affected": "264",
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      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: squashfs: Add dictionary size range check to prevent shift-out-of-bounds",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98636.json",
      "version": "3"
    }
  }
}



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