CVE-2026-6386 (GCVE-0-2026-6386)
Vulnerability from cvelistv5
Published
2026-04-22 02:33
Modified
2026-04-22 14:32
Severity ?
VLAI Severity ?
EPSS score ?
CWE
Summary
In order to apply a particular protection key to an address range, the kernel must update the corresponding page table entries. The subroutine which handled this failed to take into account the presence of 1GB largepage mappings created using the shm_create_largepage(3) interface. In particular, it would always treat a page directory page entry as pointing to another page table page.
The bug can be abused by an unprivileged user to cause pmap_pkru_update_range() to treat userspace memory as a page table page, and thus overwrite memory to which the application would otherwise not have access.
References
| URL | Tags | |
|---|---|---|
Impacted products
{
"containers": {
"adp": [
{
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "NONE",
"baseScore": 6.2,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "HIGH",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"version": "3.1"
}
},
{
"other": {
"content": {
"id": "CVE-2026-6386",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-04-22T14:26:42.409167Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-04-22T14:32:53.989Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unknown",
"modules": [
"amd64"
],
"product": "FreeBSD",
"vendor": "FreeBSD",
"versions": [
{
"lessThan": "p6",
"status": "affected",
"version": "15.0-RELEASE",
"versionType": "release"
},
{
"lessThan": "p2",
"status": "affected",
"version": "14.4-RELEASE",
"versionType": "release"
},
{
"lessThan": "p11",
"status": "affected",
"version": "14.3-RELEASE",
"versionType": "release"
},
{
"lessThan": "p12",
"status": "affected",
"version": "13.5-RELEASE",
"versionType": "release"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "Nicholas Carlini using Claude, Anthropic"
}
],
"datePublic": "2026-04-21T18:00:00.000Z",
"descriptions": [
{
"lang": "en",
"value": "In order to apply a particular protection key to an address range, the kernel must update the corresponding page table entries. The subroutine which handled this failed to take into account the presence of 1GB largepage mappings created using the shm_create_largepage(3) interface. In particular, it would always treat a page directory page entry as pointing to another page table page.\n\nThe bug can be abused by an unprivileged user to cause pmap_pkru_update_range() to treat userspace memory as a page table page, and thus overwrite memory to which the application would otherwise not have access."
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-269",
"description": "CWE-269 Improper Privilege Management",
"lang": "en",
"type": "CWE"
},
{
"cweId": "CWE-732",
"description": "CWE-732 Incorrect Permission Assignment for Critical Resource",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-04-22T02:33:24.846Z",
"orgId": "63664ac6-956c-4cba-a5d0-f46076e16109",
"shortName": "freebsd"
},
"references": [
{
"tags": [
"vendor-advisory"
],
"url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:11.amd64.asc"
}
],
"title": "Missing large page handling in pmap_pkru_update_range()"
}
},
"cveMetadata": {
"assignerOrgId": "63664ac6-956c-4cba-a5d0-f46076e16109",
"assignerShortName": "freebsd",
"cveId": "CVE-2026-6386",
"datePublished": "2026-04-22T02:33:24.846Z",
"dateReserved": "2026-04-15T19:18:20.083Z",
"dateUpdated": "2026-04-22T14:32:53.989Z",
"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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