Linux Kernel TDX Guest Quote Buffer Length Validation Mitigates OOB Read
CVE-2026-31470 Published on April 22, 2026
virt: tdx-guest: Fix handling of host controlled 'quote' buffer length
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.
Products Associated with CVE-2026-31470
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Affected Versions
Linux:- Version f4738f56d1dc62aaba69b33702a5ab098f1b8c63 and below a079a62883e3365de592cea9f7a669d8115433b0 is affected.
- Version f4738f56d1dc62aaba69b33702a5ab098f1b8c63 and below 6f3c8795ae9ba74fa10fe979293d1904712d3fb1 is affected.
- Version f4738f56d1dc62aaba69b33702a5ab098f1b8c63 and below 02ca2d9d197723696cb9cc0cb159eb7e8bf5f89b is affected.
- Version f4738f56d1dc62aaba69b33702a5ab098f1b8c63 and below c3fd16c3b98ed726294feab2f94f876290bf7b61 is affected.
- Version 6.7 is affected.
- Before 6.7 is unaffected.
- Version 6.12.80, <= 6.12.* is unaffected.
- Version 6.18.21, <= 6.18.* is unaffected.
- Version 6.19.11, <= 6.19.* is unaffected.
- Version 7.0, <= * is unaffected.