Vulnerability-Lookup

GHSA-QHPH-J75Q-5546

Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-09-13 09:32

Details

In the Linux kernel, the following vulnerability has been resolved:

cxl/ras: Fix cxl_rch_get_aer_info() out-of-bounds AER register read

cxl_rch_get_aer_info() copies the RCH Downstream Port AER capability from the RCRB MMIO block using a readl() loop bounded by sizeof(struct aer_capability_regs). This struct is a software layout and its embedded struct pcie_tlp_log is larger than the on-wire AER capability. As a result the loop reads past the mapped AER register block.

The over-read also populates the software-only tail fields including header_log.header_len. An out-of-range header_len passed to pcie_print_tlp_log() can then loop past the header log buffer and cause a second out-of-bounds read.

The read was correct when introduced, but struct pcie_tlp_log has since grown (Header Log and TLP Prefix Log sizes, header_len and flit fields), so sizeof(struct aer_capability_regs) no longer matches the physical AER capability.

Bound the read to the physical AER registers, header through the 16 byte Header Log. Zero the destination first so the software-only fields are deterministic.

Severity

7.1 (High)


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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-89731"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-11T20:20:03Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ncxl/ras: Fix cxl_rch_get_aer_info() out-of-bounds AER register read\n\ncxl_rch_get_aer_info() copies the RCH Downstream Port AER capability from\nthe RCRB MMIO block using a readl() loop bounded by sizeof(struct\naer_capability_regs). This struct is a software layout and its embedded\nstruct pcie_tlp_log is larger than the on-wire AER capability. As a\nresult the loop reads past the mapped AER register block.\n\nThe over-read also populates the software-only tail fields including\nheader_log.header_len. An out-of-range header_len passed to\npcie_print_tlp_log() can then loop past the header log buffer and cause\na second out-of-bounds read.\n\nThe read was correct when introduced, but struct pcie_tlp_log has since\ngrown (Header Log and TLP Prefix Log sizes, header_len and flit fields),\nso sizeof(struct aer_capability_regs) no longer matches the physical AER\ncapability.\n\nBound the read to the physical AER registers, header through the 16 byte\nHeader Log. Zero the destination first so the software-only fields are\ndeterministic.",
  "id": "GHSA-qhph-j75q-5546",
  "modified": "2026-09-13T09:32:29Z",
  "published": "2026-09-11T21:31:38Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89731"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/29458e62d0829cbc99435f3e44fd560f9bbf1da7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8bd3523df1319edc61cd391e695c84a4618516df"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8e3d9dbb25d3ddbe72b4542ec4f7c4e622fe0ced"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-89731 (GCVE-0-2026-89731)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:46 – Updated: 2026-09-13 06:33

Title

cxl/ras: Fix cxl_rch_get_aer_info() out-of-bounds AER register read

Summary

In the Linux kernel, the following vulnerability has been resolved: cxl/ras: Fix cxl_rch_get_aer_info() out-of-bounds AER register read cxl_rch_get_aer_info() copies the RCH Downstream Port AER capability from the RCRB MMIO block using a readl() loop bounded by sizeof(struct aer_capability_regs). This struct is a software layout and its embedded struct pcie_tlp_log is larger than the on-wire AER capability. As a result the loop reads past the mapped AER register block. The over-read also populates the software-only tail fields including header_log.header_len. An out-of-range header_len passed to pcie_print_tlp_log() can then loop past the header log buffer and cause a second out-of-bounds read. The read was correct when introduced, but struct pcie_tlp_log has since grown (Header Log and TLP Prefix Log sizes, header_len and flit fields), so sizeof(struct aer_capability_regs) no longer matches the physical AER capability. Bound the read to the physical AER registers, header through the 16 byte Header Log. Zero the destination first so the software-only fields are deterministic.

Severity

7.1 (High)


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

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/8bd3523df1319edc6…
https://git.kernel.org/stable/c/8e3d9dbb25d3ddbe7…
https://git.kernel.org/stable/c/29458e62d0829cbc9…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 6ac07883dbb5f60f7bc56a13b7a84a382aa9c1ab , < 8bd3523df1319edc61cd391e695c84a4618516df (git) Affected: 6ac07883dbb5f60f7bc56a13b7a84a382aa9c1ab , < 8e3d9dbb25d3ddbe72b4542ec4f7c4e622fe0ced (git) Affected: 6ac07883dbb5f60f7bc56a13b7a84a382aa9c1ab , < 29458e62d0829cbc99435f3e44fd560f9bbf1da7 (git)
Linux	Linux	Affected: 6.7 Unaffected: 0 , < 6.7 (semver) Unaffected: 6.18.51 , ≤ 6.18.* (semver) Unaffected: 7.2.4 , ≤ 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/cxl/core/ras_rch.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "8bd3523df1319edc61cd391e695c84a4618516df",
              "status": "affected",
              "version": "6ac07883dbb5f60f7bc56a13b7a84a382aa9c1ab",
              "versionType": "git"
            },
            {
              "lessThan": "8e3d9dbb25d3ddbe72b4542ec4f7c4e622fe0ced",
              "status": "affected",
              "version": "6ac07883dbb5f60f7bc56a13b7a84a382aa9c1ab",
              "versionType": "git"
            },
            {
              "lessThan": "29458e62d0829cbc99435f3e44fd560f9bbf1da7",
              "status": "affected",
              "version": "6ac07883dbb5f60f7bc56a13b7a84a382aa9c1ab",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/cxl/core/ras_rch.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.7"
            },
            {
              "lessThan": "6.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "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": "6.18.51",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncxl/ras: Fix cxl_rch_get_aer_info() out-of-bounds AER register read\n\ncxl_rch_get_aer_info() copies the RCH Downstream Port AER capability from\nthe RCRB MMIO block using a readl() loop bounded by sizeof(struct\naer_capability_regs). This struct is a software layout and its embedded\nstruct pcie_tlp_log is larger than the on-wire AER capability. As a\nresult the loop reads past the mapped AER register block.\n\nThe over-read also populates the software-only tail fields including\nheader_log.header_len. An out-of-range header_len passed to\npcie_print_tlp_log() can then loop past the header log buffer and cause\na second out-of-bounds read.\n\nThe read was correct when introduced, but struct pcie_tlp_log has since\ngrown (Header Log and TLP Prefix Log sizes, header_len and flit fields),\nso sizeof(struct aer_capability_regs) no longer matches the physical AER\ncapability.\n\nBound the read to the physical AER registers, header through the 16 byte\nHeader Log. Zero the destination first so the software-only fields are\ndeterministic."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable cxl_rch_get_aer_info() runs only from the host PCI AER IRQ path (aer_isr \u2192 cxl_rch_handle_error \u2192 cxl_error_detected/cxl_cor_error_detected) on Restricted CXL Host/Device topologies; it is not reachable from network protocols. Local access to a CXL host is the applicable vector and is higher severity than physical card insertion.\nAC:L - Once an RCH downstream-port AER event is raised, the readl() loop copies sizeof(struct aer_capability_regs) (100 bytes) instead of the 44-byte physical Header Log with no race. Unimplemented RCRB MMIO commonly returns 0xFFFFFFFF, so header_len/flit reliably drive a second out-of-bounds read in pcie_print_tlp_log().\nPR:L - The AER ISR and CXL error handlers perform no capability check. An unprivileged local user, or a guest with a passed-through CXL endpoint, can induce CXL protocol/AER errors that reach this path; init-namespace root is not required.\nUI:N - PCIe AER interrupts are dispatched automatically by aer_isr() into the CXL PCI error handlers; no victim mount, file open, or other interactive action is required.\nS:U - The MMIO and stack out-of-bounds reads occur in the host kernel CXL/PCI AER code and do not cross a VM, IOMMU, or sandbox security boundary.\nC:H - Adjacent RCRB MMIO is copied into software-only fields including header_log.header_len; pcie_print_tlp_log() then reads log-\u003edw[] with a u8 index up to 255 past the 14-dword array, leaking up to ~1KB of kernel stack and RCRB contents to dmesg.\nI:N - Both issues are out-of-bounds reads only: MMIO is copied into a correctly sized stack aer_capability_regs, and pcie_print_tlp_log() only reads log-\u003edw[]. In-bounds status writel()s and length-capped scnprintf() provide no write or control-flow primitive.\nA:H - The unbounded stack read in pcie_print_tlp_log() and readl() past the physical AER capability in the RCRB can fault or raise a platform machine-check, producing a kernel oops/panic; uncorrectable CXL RAS handling can also disable CXL.mem."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-13T06:33:45.296Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/8bd3523df1319edc61cd391e695c84a4618516df"
        },
        {
          "url": "https://git.kernel.org/stable/c/8e3d9dbb25d3ddbe72b4542ec4f7c4e622fe0ced"
        },
        {
          "url": "https://git.kernel.org/stable/c/29458e62d0829cbc99435f3e44fd560f9bbf1da7"
        }
      ],
      "title": "cxl/ras: Fix cxl_rch_get_aer_info() out-of-bounds AER register read",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89731",
    "datePublished": "2026-09-11T19:46:41.312Z",
    "dateReserved": "2026-09-11T19:38:34.760Z",
    "dateUpdated": "2026-09-13T06:33:45.296Z",
    "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.

Detection rules are retrieved from Rulezet.

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.