Vulnerability-Lookup

FKIE_CVE-2026-90191

Vulnerability from fkie_nvd - Published: 2026-09-17 17:17 - Updated: 2026-09-18 18:17

Severity

8.4 (High) - CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: mailbox: riscv-sbi-mpxy: validate RPMI notification lengths The SBI return value controls how many bytes are copied from shared memory into the RPMI notification buffer. It is not validated against the negotiated shared-memory size before that copy. The event walker also uses a reversed loop condition and can inspect a short event record. Validate the complete notification length before copying it, iterate only while a full event header remains, and stop when a declared event payload extends beyond the copied notification data.

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/11d5af151bcbe78f5a579e0faecd3be9cea0399a
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/c7bc5e7677bcda7a446d63b989cfaa3fe91d6b76
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/cbc24bce70dfd91c7b2f53b4fa896e9a4b6d6a6b

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/mailbox/riscv-sbi-mpxy-mbox.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "cbc24bce70dfd91c7b2f53b4fa896e9a4b6d6a6b",
              "status": "affected",
              "version": "bf3022a4eb119c6b4e3424d6b19d8bfdfbc9bb57",
              "versionType": "git"
            },
            {
              "lessThan": "c7bc5e7677bcda7a446d63b989cfaa3fe91d6b76",
              "status": "affected",
              "version": "bf3022a4eb119c6b4e3424d6b19d8bfdfbc9bb57",
              "versionType": "git"
            },
            {
              "lessThan": "11d5af151bcbe78f5a579e0faecd3be9cea0399a",
              "status": "affected",
              "version": "bf3022a4eb119c6b4e3424d6b19d8bfdfbc9bb57",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/mailbox/riscv-sbi-mpxy-mbox.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.18"
            },
            {
              "lessThan": "6.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmailbox: riscv-sbi-mpxy: validate RPMI notification lengths\n\nThe SBI return value controls how many bytes are copied from shared\nmemory into the RPMI notification buffer. It is not validated against\nthe negotiated shared-memory size before that copy. The event walker\nalso uses a reversed loop condition and can inspect a short event record.\n\nValidate the complete notification length before copying it, iterate only\nwhile a full event header remains, and stop when a declared event payload\nextends beyond the copied notification data."
    }
  ],
  "id": "CVE-2026-90191",
  "lastModified": "2026-09-18T18:17:45.823",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 8.4,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.5,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-17T17:17:13.810",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/11d5af151bcbe78f5a579e0faecd3be9cea0399a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c7bc5e7677bcda7a446d63b989cfaa3fe91d6b76"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/cbc24bce70dfd91c7b2f53b4fa896e9a4b6d6a6b"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

CVE-2026-90191 (GCVE-0-2026-90191)

Vulnerability from cvelistv5 – Published: 2026-09-17 16:07 – Updated: 2026-09-18 17:53

Title

mailbox: riscv-sbi-mpxy: validate RPMI notification lengths

Summary

Severity

8.4 (High)


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

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/cbc24bce70dfd91c7…
https://git.kernel.org/stable/c/c7bc5e7677bcda7a4…
https://git.kernel.org/stable/c/11d5af151bcbe78f5…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: bf3022a4eb119c6b4e3424d6b19d8bfdfbc9bb57 , < cbc24bce70dfd91c7b2f53b4fa896e9a4b6d6a6b (git) Affected: bf3022a4eb119c6b4e3424d6b19d8bfdfbc9bb57 , < c7bc5e7677bcda7a446d63b989cfaa3fe91d6b76 (git) Affected: bf3022a4eb119c6b4e3424d6b19d8bfdfbc9bb57 , < 11d5af151bcbe78f5a579e0faecd3be9cea0399a (git)
Linux	Linux	Affected: 6.18 Unaffected: 0 , < 6.18 (semver) Unaffected: 6.18.52 , ≤ 6.18.* (semver) Unaffected: 7.2.6 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/mailbox/riscv-sbi-mpxy-mbox.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "cbc24bce70dfd91c7b2f53b4fa896e9a4b6d6a6b",
              "status": "affected",
              "version": "bf3022a4eb119c6b4e3424d6b19d8bfdfbc9bb57",
              "versionType": "git"
            },
            {
              "lessThan": "c7bc5e7677bcda7a446d63b989cfaa3fe91d6b76",
              "status": "affected",
              "version": "bf3022a4eb119c6b4e3424d6b19d8bfdfbc9bb57",
              "versionType": "git"
            },
            {
              "lessThan": "11d5af151bcbe78f5a579e0faecd3be9cea0399a",
              "status": "affected",
              "version": "bf3022a4eb119c6b4e3424d6b19d8bfdfbc9bb57",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/mailbox/riscv-sbi-mpxy-mbox.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.18"
            },
            {
              "lessThan": "6.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.52",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.6",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmailbox: riscv-sbi-mpxy: validate RPMI notification lengths\n\nThe SBI return value controls how many bytes are copied from shared\nmemory into the RPMI notification buffer. It is not validated against\nthe negotiated shared-memory size before that copy. The event walker\nalso uses a reversed loop condition and can inspect a short event record.\n\nValidate the complete notification length before copying it, iterate only\nwhile a full event header remains, and stop when a declared event payload\nextends beyond the copied notification data."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.4,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The malformed length is sret.value from sbi_ecall(SBI_EXT_MPXY, SBI_EXT_MPXY_GET_NOTIFICATION_EVENTS) in mpxy_get_notifications(), invoked by mpxy_mbox_irq_thread via mpxy_mbox_peek_data when the MPXY channel MSI fires. That SBI shared-memory/return path is on-chip firmware or an RPMI platform MCU, not a network, Bluetooth, or USB protocol.\nAC:L - A malicious SBI MPXY implementation fully controls sret.value. Returning a length greater than mpxy_shmem_size-sizeof(*notif_data), or a negative value so that sret.value+16 wraps to size_t, makes memcpy() overflow the mpxy_shmem_size mchan-\u003enotif buffer on every successful GET_NOTIFICATION_EVENTS with no race.\nPR:N - mpxy_mbox_irq_thread has no capable() or credential check. After rpmi_clk_probe()/rpmi_sysmsi_probe() call mbox_request_channel(), mpxy_mbox_startup() enables the MSI via request_threaded_irq(); compromised SBI firmware or the RPMI microcontroller can fire that IRQ and return the bad length without a Linux user account.\nUI:N - mpxy_mbox_startup() enables MSI and events when clk-rpmi or rpmi-sysmsi bind at boot via mbox_request_channel(). The firmware then delivers GET_NOTIFICATION_EVENTS through mpxy_mbox_irq_thread; no victim must open a device, mount a filesystem, or otherwise interact.\nS:U - memcpy() corrupts host kernel heap around mchan-\u003enotif. KVM\u0027s vcpu_sbi_ext_mpxy only forwards guest SBI MPXY ECALLs to userspace (and is default_disabled) and never enters this mailbox driver, so this is not a guest-to-host escape.\nC:H - memcpy(notif_data, mpxy-\u003eshmem, sret.value+16) over-reads past the per-CPU shmem pages and writes firmware-controlled bytes past the mpxy_shmem_size kmalloc notif buffer, a heap overflow that can be leveraged for kernel memory disclosure.\nI:H - The same unbounded memcpy is a heap out-of-bounds write of SBI-controlled shared-memory contents past mchan-\u003enotif, smashing adjacent slab objects and enabling control-flow hijacking.\nA:H - Copying a huge or wrapped sret.value into the mpxy_shmem_size notif allocation walks unmapped heap/guard pages or corrupts allocator metadata, causing a kernel oops or panic in mpxy_mbox_irq_thread."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-18T17:53:38.782Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/cbc24bce70dfd91c7b2f53b4fa896e9a4b6d6a6b"
        },
        {
          "url": "https://git.kernel.org/stable/c/c7bc5e7677bcda7a446d63b989cfaa3fe91d6b76"
        },
        {
          "url": "https://git.kernel.org/stable/c/11d5af151bcbe78f5a579e0faecd3be9cea0399a"
        }
      ],
      "title": "mailbox: riscv-sbi-mpxy: validate RPMI notification lengths",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90191",
    "datePublished": "2026-09-17T16:07:12.339Z",
    "dateReserved": "2026-09-11T19:38:34.792Z",
    "dateUpdated": "2026-09-18T17:53:38.782Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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FKIE_CVE-2026-90191

CVE-2026-90191 (GCVE-0-2026-90191)

Tags

Sightings

Nomenclature

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