Vulnerability-Lookup

GHSA-99G5-MWJ2-6XJQ

Vulnerability from github – Published: 2026-04-22 03:31 – Updated: 2026-04-22 15:31

Details

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.

Severity ?

6.2 (Medium)


                  
                    CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

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{
  "affected": [],
  "aliases": [
    "CVE-2026-6386"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-269"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-22T03:16:01Z",
    "severity": "MODERATE"
  },
  "details": "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.",
  "id": "GHSA-99g5-mwj2-6xjq",
  "modified": "2026-04-22T15:31:39Z",
  "published": "2026-04-22T03:31:36Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-6386"
    },
    {
      "type": "WEB",
      "url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:11.amd64.asc"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-6386 (GCVE-0-2026-6386)

Vulnerability from cvelistv5 – Published: 2026-04-22 02:33 – Updated: 2026-04-22 14:32

Title

Missing large page handling in pmap_pkru_update_range()

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.

Severity ?

6.2 (Medium)


                        
                          CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CWE

CWE-269 - Improper Privilege Management
CWE-732 - Incorrect Permission Assignment for Critical Resource

Assigner

freebsd

References

URL

Tags

https://security.freebsd.org/advisories/FreeBSD-S…

vendor-advisory

Impacted products

	Vendor	Product	Version
	FreeBSD	FreeBSD	Affected: 15.0-RELEASE , < p6 (release) Affected: 14.4-RELEASE , < p2 (release) Affected: 14.3-RELEASE , < p11 (release) Affected: 13.5-RELEASE , < p12 (release)

Date Public ?

2026-04-21 18:00

Credits

Nicholas Carlini using Claude, Anthropic

Show details on NVD website

JSON

To clipboard

{
  "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"
}

Sightings

Author	Source	Type	Date

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.

Action not permitted

GHSA-99G5-MWJ2-6XJQ

CVE-2026-6386 (GCVE-0-2026-6386)

Tags

Sightings

Nomenclature