CVE-2026-31470 (GCVE-0-2026-31470)

Vulnerability from cvelistv5 – Published: 2026-04-22 13:53 – Updated: 2026-08-05 12:22
VLAI
Title
virt: tdx-guest: Fix handling of host controlled 'quote' buffer length
Summary
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.
Severity
7.1 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: f4738f56d1dc62aaba69b33702a5ab098f1b8c63 , < a079a62883e3365de592cea9f7a669d8115433b0 (git)
Affected: f4738f56d1dc62aaba69b33702a5ab098f1b8c63 , < 6f3c8795ae9ba74fa10fe979293d1904712d3fb1 (git)
Affected: f4738f56d1dc62aaba69b33702a5ab098f1b8c63 , < 02ca2d9d197723696cb9cc0cb159eb7e8bf5f89b (git)
Affected: f4738f56d1dc62aaba69b33702a5ab098f1b8c63 , < c3fd16c3b98ed726294feab2f94f876290bf7b61 (git)
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Linux Linux Affected: 6.7
Unaffected: 0 , < 6.7 (semver)
Unaffected: 6.12.80 , ≤ 6.12.* (semver)
Unaffected: 6.18.21 , ≤ 6.18.* (semver)
Unaffected: 6.19.11 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
Create a notification for this product.
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvirt: tdx-guest: Fix handling of host controlled \u0027quote\u0027 buffer length\n\nValidate host controlled value `quote_buf-\u003eout_len` that determines how\nmany bytes of the quote are copied out to guest userspace. In TDX\nenvironments with remote attestation, quotes are not considered private,\nand can be forwarded to an attestation server.\n\nCatch scenarios where the host specifies a response length larger than\nthe guest\u0027s allocation, or otherwise races modifying the response while\nthe guest consumes it.\n\nThis prevents contents beyond the pages allocated for `quote_buf`\n(up to TSM_REPORT_OUTBLOB_MAX) from being read out to guest userspace,\nand possibly forwarded in attestation requests.\n\nRecall that some deployments want per-container configs-tsm-report\ninterfaces, so the leak may cross container protection boundaries, not\njust local root."
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    "dateReserved": "2026-03-09T15:48:24.097Z",
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    "redhat_vex": {
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      "current_release_date": "2026-07-02T17:14:01+00:00",
      "cve": "CVE-2026-31470",
      "id": "CVE-2026-31470",
      "initial_release_date": "2026-04-22T00:00:00+00:00",
      "product_status:known_affected": "260",
      "product_status:known_not_affected": "14",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: virt: tdx-guest: Fix handling of host controlled \u0027quote\u0027 buffer length",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-31470.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-07-19T17:41:26Z",
      "cve": "CVE-2026-31470",
      "id": "CVE-2026-31470",
      "initial_release_date": "2026-04-23T01:25:53Z",
      "product_status:first_fixed": "2",
      "product_status:known_affected": "414",
      "product_status:known_not_affected": "136",
      "product_status:recommended": "394",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-31470",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-31470.json",
      "version": "21"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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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.