CVE-2026-31698

Kernel-memory disclosure via failed PDH export

Published May 1, 2026 · Updated May 1, 2026

Out-of-bounds read in the Linux kernel allows local users to disclose kernel memory through a crafted SEV PDH export ioctl. In sev_ioctl_do_pdh_export, a failed firmware command updates required blob lengths beyond the allocated buffers, but copy_to_user still uses those larger lengths. The path requires local access to /dev/sev and undersized nonzero certificate buffers; it exposes adjacent kernel heap data and can crash a hardened kernel.

CVSS severity7.1
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in the Linux kernel allows local users to disclose kernel memory through a crafted SEV PDH export ioctl. In sev_ioctl_do_pdh_export, a failed firmware command updates required blob lengths beyond the allocated buffers, but copy_to_user still uses those larger lengths. The path requires local access to /dev/sev and undersized nonzero certificate buffers; it exposes adjacent kernel heap data and can crash a hardened kernel.

The record

CVE
CVE-2026-31698
Published
May 1, 2026
Updated
May 1, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-787, T1005
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 1, 2026CVE publishedPublication date reported by the CVE source.
  2. May 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.16
  2. Affected versionversion=76a2b524a4b1d6dc0f2421f9854a01d55d5e5436 <051e51aa55fd4cdc3e8283cf4476aeeb5f563274
  3. Affected versionversion=76a2b524a4b1d6dc0f2421f9854a01d55d5e5436 <50808c13452dae43a2c90b1bbbf9daa16501ce70
  4. Affected versionversion=76a2b524a4b1d6dc0f2421f9854a01d55d5e5436 <78b97e43d0b3e674d9d49ae56937b11e2ba3fcaf
  5. Affected versionversion=76a2b524a4b1d6dc0f2421f9854a01d55d5e5436 <b5c14bd4da1f376f385722fe1da993f1edab6472
  6. Affected versionversion=76a2b524a4b1d6dc0f2421f9854a01d55d5e5436 <e76239fed3cffd6d304d8ca3ce23984fd24f57d3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=4.16; version=76a2b524a4b1d6dc0f2421f9854a01d55d5e5436 <051e51aa55fd4cdc3e8283cf4476aeeb5f563274; version=76a2b524a4b1d6dc0f2421f9854a01d55d5e5436 <50808c13452dae43a2c90b1bbbf9daa16501ce70; version=76a2b524a4b1d6dc0f2421f9854a01d55d5e5436 <78b97e43d0b3e674d9d49ae56937b11e2ba3fcaf; version=76a2b524a4b1d6dc0f2421f9854a01d55d5e5436 <b5c14bd4da1f376f385722fe1da993f1edab6472; version=76a2b524a4b1d6dc0f2421f9854a01d55d5e5436 <e76239fed3cffd6d304d8ca3ce23984fd24f57d3

Published CVSS scores

7.1kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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