CVE-2026-31478 (GCVE-0-2026-31478)
Vulnerability from cvelistv5
Published
2026-04-22 13:54
Modified
2026-04-27 14:03
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len()
After this commit (e2b76ab8b5c9 "ksmbd: add support for read compound"),
response buffer management was changed to use dynamic iov array.
In the new design, smb2_calc_max_out_buf_len() expects the second
argument (hdr2_len) to be the offset of ->Buffer field in the
response structure, not a hardcoded magic number.
Fix the remaining call sites to use the correct offsetof() value.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: f2283680a80571ca82d710bc6ecd8f8beac67d63 Version: 9f297df20d93411c0b4ddad7f88ba04a7cd36e77 Version: e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d Version: e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d Version: e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d Version: e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d Version: e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d |
||
{
"containers": {
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],
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"vendor": "Linux",
"versions": [
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"version": "6.6"
},
{
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"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.203",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.168",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.131",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.80",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.21",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.19.*",
"status": "unaffected",
"version": "6.19.11",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
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"vulnerable": true
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{
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{
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"negate": false,
"operator": "OR"
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],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len()\n\nAfter this commit (e2b76ab8b5c9 \"ksmbd: add support for read compound\"),\nresponse buffer management was changed to use dynamic iov array.\nIn the new design, smb2_calc_max_out_buf_len() expects the second\nargument (hdr2_len) to be the offset of -\u003eBuffer field in the\nresponse structure, not a hardcoded magic number.\nFix the remaining call sites to use the correct offsetof() value."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-04-27T14:03:32.354Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/70b4c414889492c522b6e4331562360f49be2361"
},
{
"url": "https://git.kernel.org/stable/c/9a7166f0ef8cbb7bb48dd05e2471d995566003f5"
},
{
"url": "https://git.kernel.org/stable/c/c3a89e3ec1ccf64fa6a34e391e1581ebbcba8683"
},
{
"url": "https://git.kernel.org/stable/c/6aef1765d6807e0f027cd87f6ac973eb0879a46d"
},
{
"url": "https://git.kernel.org/stable/c/80824c7e527b70cf9039534e60aff592e8f209d1"
},
{
"url": "https://git.kernel.org/stable/c/4cb537ae4f37d7d0f617815ed4bed7173fb50861"
},
{
"url": "https://git.kernel.org/stable/c/0e55f63dd08f09651d39e1b709a91705a8a0ddcb"
}
],
"title": "ksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len()",
"x_generator": {
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"cveMetadata": {
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"assignerShortName": "Linux",
"cveId": "CVE-2026-31478",
"datePublished": "2026-04-22T13:54:06.157Z",
"dateReserved": "2026-03-09T15:48:24.098Z",
"dateUpdated": "2026-04-27T14:03:32.354Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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