# CVE-2026-31470: CVE-2026-31470

Status: published. Published: 2026-04-22. Updated: 2026-11-11.

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

virt: tdx-guest: Fix handling of host controlled 'quote' buffer length

Validate host controlled value `quote_buf->out_len` that determines how
many bytes of the quote are copied out to guest userspace. In TDX
environments with remote attestation, quotes are not considered private,
and can be forwarded to an attestation server.

Catch scenarios where the host specifies a response length larger than
the guest's allocation, or otherwise races modifying the response while
the guest consumes it.

This prevents contents beyond the pages allocated for `quote_buf`
(up to TSM_REPORT_OUTBLOB_MAX) from being read out to guest userspace,
and possibly forwarded in attestation requests.

Recall that some deployments want per-container configs-tsm-report
interfaces, so the leak may cross container protection boundaries, not
just local root.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) — https://git.kernel.org/stable/c/02ca2d9d197723696cb9cc0cb159eb7e8bf5f89b
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) — https://git.kernel.org/stable/c/6f3c8795ae9ba74fa10fe979293d1904712d3fb1
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) — https://git.kernel.org/stable/c/a079a62883e3365de592cea9f7a669d8115433b0
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) — https://git.kernel.org/stable/c/c3fd16c3b98ed726294feab2f94f876290bf7b61

## Affected products and versions

- linux / linux_kernel: ≥ 6.7; < 6.12.80 (affected, custom). Source: NVD
- linux / linux_kernel: ≥ 6.13; < 6.18.21 (affected, custom). Source: NVD
- linux / linux_kernel: ≥ 6.19; < 6.19.11 (affected, custom). Source: NVD
- linux / linux_kernel: 7.0 (affected, custom). Source: NVD

## NVD configuration conditions

Affected CPE matches depend on the following AND/OR and negation conditions:

```json
[
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.12.80",
            "versionStartIncluding": "6.7",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.18.21",
            "versionStartIncluding": "6.13",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.19.11",
            "versionStartIncluding": "6.19",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "OR"
  }
]
```

## Severity and prioritization

- CVSS 3.1: 7.1 (high); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H; source: NVD: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: exploitation none; automatable no; technical impact partial; source NVD SSVC: 134c704f-9b21-4f2e-91b3-4a467353bcc0

- Weaknesses: CWE-787, CWE-125

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/02ca2d9d197723696cb9cc0cb159eb7e8bf5f89b (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/6f3c8795ae9ba74fa10fe979293d1904712d3fb1 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/a079a62883e3365de592cea9f7a669d8115433b0 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/c3fd16c3b98ed726294feab2f94f876290bf7b61 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

## Provenance

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31470; retrieved 2026-11-12; source updated 2026-11-11

Revision: e05b3c4a43823dd6e62cbf90ab0e8f0b38dd5d4e558e8838a056c41658418d94

Canonical: https://y2.dev/cve/CVE-2026-31470

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