CVE-2026-98636
Status: ReceivedUnscored—
Severity—Unscored
Exploitation probability0.18 %higher than 7% of CVEs
Active exploitationNonot in the CISA catalog
Public exploitNot knownno public code found
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.
Fix it by adding a dictionary size range check before the shift operation.
Technical details traces, logs and code from the original report
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-boundsCVSS
NVD hasn't assigned a CVSS score to this CVE (common since the April 2026 policy change).
Exploitation probability (EPSS)
- Probability of exploitation in the next 30 days
- 0.18 %
- Percentile among all scored CVEs
- 7
- Score date
- 10/20/2026
EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).
Affected technologies (1)
⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.
References
Show 8 references
- https://git.kernel.org/stable/c/0cb85377daaefb4ce5ce72975f2deb27ee0e0cad
- https://git.kernel.org/stable/c/1f7745fb3580152ca902ef181b605f33cabfb1d0
- https://git.kernel.org/stable/c/7a1c293e7aa17f1afaee0684e0e931fe23a5a6b1
- https://git.kernel.org/stable/c/88c673a0bd233df44ca0020da82f4fd3876de27a
- https://git.kernel.org/stable/c/9d9c5c218ea356a1d88765214ad2919605280ab1
- https://git.kernel.org/stable/c/b02948a23455f8190a53887b2d2c13ae1d360cea
- https://git.kernel.org/stable/c/c68e0068a236f9a7dfc19720bdf11e5d80a85089
- https://git.kernel.org/stable/c/e1ca4e3a380ef3e8f46ce006f1146392e3f32c98
Raw JSON (NVD)
Show
{
"id": "CVE-2026-98636",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "ff750311d30acc9564ef577050794953eee59f01",
"lessThan": "b02948a23455f8190a53887b2d2c13ae1d360cea",
"versionType": "git"
},
{
"status": "affected",
"version": "ff750311d30acc9564ef577050794953eee59f01",
"lessThan": "9d9c5c218ea356a1d88765214ad2919605280ab1",
"versionType": "git"
},
{
"status": "affected",
"version": "ff750311d30acc9564ef577050794953eee59f01",
"lessThan": "7a1c293e7aa17f1afaee0684e0e931fe23a5a6b1",
"versionType": "git"
},
{
"status": "affected",
"version": "ff750311d30acc9564ef577050794953eee59f01",
"lessThan": "c68e0068a236f9a7dfc19720bdf11e5d80a85089",
"versionType": "git"
},
{
"status": "affected",
"version": "ff750311d30acc9564ef577050794953eee59f01",
"lessThan": "88c673a0bd233df44ca0020da82f4fd3876de27a",
"versionType": "git"
},
{
"status": "affected",
"version": "ff750311d30acc9564ef577050794953eee59f01",
"lessThan": "0cb85377daaefb4ce5ce72975f2deb27ee0e0cad",
"versionType": "git"
},
{
"status": "affected",
"version": "ff750311d30acc9564ef577050794953eee59f01",
"lessThan": "e1ca4e3a380ef3e8f46ce006f1146392e3f32c98",
"versionType": "git"
},
{
"status": "affected",
"version": "ff750311d30acc9564ef577050794953eee59f01",
"lessThan": "1f7745fb3580152ca902ef181b605f33cabfb1d0",
"versionType": "git"
}
],
"programFiles": [
"fs/squashfs/xz_wrapper.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.39"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "2.6.39",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.271",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.222",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.189",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.158",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.112",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.55",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.9",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/squashfs/xz_wrapper.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-10-18T16:17:16.700",
"references": [
{
"url": "https://git.kernel.org/stable/c/0cb85377daaefb4ce5ce72975f2deb27ee0e0cad",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/1f7745fb3580152ca902ef181b605f33cabfb1d0",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/7a1c293e7aa17f1afaee0684e0e931fe23a5a6b1",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/88c673a0bd233df44ca0020da82f4fd3876de27a",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/9d9c5c218ea356a1d88765214ad2919605280ab1",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/b02948a23455f8190a53887b2d2c13ae1d360cea",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/c68e0068a236f9a7dfc19720bdf11e5d80a85089",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/e1ca4e3a380ef3e8f46ce006f1146392e3f32c98",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"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->dict_size) - 1;<----opts->dict_size=0, n=-1\n if (opts->dict_size != (1 << n) && opts->dict_size !=\n\t \t(1 << n) + (1 << (n + 1))) <----shift-out-of-bounds\n\nFix it by adding a dictionary size range check before the shift operation."
}
],
"lastModified": "2026-10-19T10:19:27.837",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}