Vulnerability-Lookup

GHSA-H63X-7924-M7QF

Vulnerability from github – Published: 2026-03-26 09:30 – Updated: 2026-04-01 15:30

Details

As kgssapi.ko's RPCSEC_GSS implementation is vulnerable, remote code execution in the kernel is possible by an authenticated user that is able to send packets to the kernel's NFS server while kgssapi.ko is loaded into the kernel.

In userspace, applications which have librpcgss_sec loaded and run an RPC server are vulnerable to remote code execution from any client able to send it packets. We are not aware of any such applications in the FreeBSD base system.

Severity ?

8.8 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-4747"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-121"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-03-26T07:16:20Z",
    "severity": "HIGH"
  },
  "details": "Each RPCSEC_GSS data packet is validated by a routine which checks a signature in the packet.  This routine copies a portion of the packet into a stack buffer, but fails to ensure that the buffer is sufficiently large, and a malicious client can trigger a stack overflow.  Notably, this does not require the client to authenticate itself first.\n\nAs kgssapi.ko\u0027s RPCSEC_GSS implementation is vulnerable, remote code execution in the kernel is possible by an authenticated user that is able to send packets to the kernel\u0027s NFS server while kgssapi.ko is loaded into the kernel.\n\nIn userspace, applications which have librpcgss_sec loaded and run an RPC server are vulnerable to remote code execution from any client able to send it packets.  We are not aware of any such applications in the FreeBSD base system.",
  "id": "GHSA-h63x-7924-m7qf",
  "modified": "2026-04-01T15:30:57Z",
  "published": "2026-03-26T09:30:28Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-4747"
    },
    {
      "type": "WEB",
      "url": "https://github.com/califio/publications/blob/main/MADBugs/CVE-2026-4747/exploit.py"
    },
    {
      "type": "WEB",
      "url": "https://github.com/califio/publications/tree/main/MADBugs/CVE-2026-4747"
    },
    {
      "type": "WEB",
      "url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:08.rpcsec_gss.asc"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-4747 (GCVE-0-2026-4747)

Vulnerability from cvelistv5 – Published: 2026-03-26 06:21 – Updated: 2026-04-02 03:55

Title

Remote code execution via RPCSEC_GSS packet validation

Summary

Each RPCSEC_GSS data packet is validated by a routine which checks a signature in the packet. This routine copies a portion of the packet into a stack buffer, but fails to ensure that the buffer is sufficiently large, and a malicious client can trigger a stack overflow. Notably, this does not require the client to authenticate itself first. As kgssapi.ko's RPCSEC_GSS implementation is vulnerable, remote code execution in the kernel is possible by an authenticated user that is able to send packets to the kernel's NFS server while kgssapi.ko is loaded into the kernel. In userspace, applications which have librpcgss_sec loaded and run an RPC server are vulnerable to remote code execution from any client able to send it packets. We are not aware of any such applications in the FreeBSD base system.

Severity ?

8.8 (High)


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

CWE

CWE-121 - Stack-based Buffer Overflow

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 , < p5 (release) Affected: 14.4-RELEASE , < p1 (release) Affected: 14.3-RELEASE , < p10 (release) Affected: 13.5-RELEASE , < p11 (release)

Date Public ?

2026-03-26 05:00

Credits

Nicholas Carlini using Claude, Anthropic

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 8.8,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "LOW",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-4747",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-26T00:00:00+00:00",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-02T03:55:35.253Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/califio/publications/blob/main/MADBugs/CVE-2026-4747/exploit.py"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2026-04-01T14:07:04.429Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "https://github.com/califio/publications/tree/main/MADBugs/CVE-2026-4747"
          }
        ],
        "title": "CVE Program Container",
        "x_generator": {
          "engine": "ADPogram 0.0.1"
        }
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "modules": [
            "rpcsec_gss"
          ],
          "product": "FreeBSD",
          "vendor": "FreeBSD",
          "versions": [
            {
              "lessThan": "p5",
              "status": "affected",
              "version": "15.0-RELEASE",
              "versionType": "release"
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            {
              "lessThan": "p1",
              "status": "affected",
              "version": "14.4-RELEASE",
              "versionType": "release"
            },
            {
              "lessThan": "p10",
              "status": "affected",
              "version": "14.3-RELEASE",
              "versionType": "release"
            },
            {
              "lessThan": "p11",
              "status": "affected",
              "version": "13.5-RELEASE",
              "versionType": "release"
            }
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        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Nicholas Carlini using Claude, Anthropic"
        }
      ],
      "datePublic": "2026-03-26T05:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "Each RPCSEC_GSS data packet is validated by a routine which checks a signature in the packet.  This routine copies a portion of the packet into a stack buffer, but fails to ensure that the buffer is sufficiently large, and a malicious client can trigger a stack overflow.  Notably, this does not require the client to authenticate itself first.\n\nAs kgssapi.ko\u0027s RPCSEC_GSS implementation is vulnerable, remote code execution in the kernel is possible by an authenticated user that is able to send packets to the kernel\u0027s NFS server while kgssapi.ko is loaded into the kernel.\n\nIn userspace, applications which have librpcgss_sec loaded and run an RPC server are vulnerable to remote code execution from any client able to send it packets.  We are not aware of any such applications in the FreeBSD base system."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-121",
              "description": "CWE-121: Stack-based Buffer Overflow",
              "lang": "en",
              "type": "CWE"
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          ]
        }
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      "providerMetadata": {
        "dateUpdated": "2026-03-26T06:21:12.735Z",
        "orgId": "63664ac6-956c-4cba-a5d0-f46076e16109",
        "shortName": "freebsd"
      },
      "references": [
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:08.rpcsec_gss.asc"
        }
      ],
      "title": "Remote code execution via RPCSEC_GSS packet validation",
      "x_generator": {
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  "cveMetadata": {
    "assignerOrgId": "63664ac6-956c-4cba-a5d0-f46076e16109",
    "assignerShortName": "freebsd",
    "cveId": "CVE-2026-4747",
    "datePublished": "2026-03-26T06:21:12.735Z",
    "dateReserved": "2026-03-24T03:57:38.500Z",
    "dateUpdated": "2026-04-02T03:55:35.253Z",
    "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-H63X-7924-M7QF

CVE-2026-4747 (GCVE-0-2026-4747)

Tags

Sightings

Nomenclature