CVE-2026-31729

Out-of-bounds access via unchecked connector index

Published May 1, 2026 · Updated May 1, 2026

Improper index validation in the Linux Kernel UCSI driver allows local users to trigger an out-of-bounds access through a crafted CCI. ucsi_connector_change() indexes the connector array with a 7-bit value parsed by ucsi_notify_common() without checking it against the allocated connector count. Reachability requires a malicious or malfunctioning UCSI device to supply the bogus value, and the access can compromise kernel confidentiality, integrity, and availability.

CVSS severity7.8
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

Improper index validation in the Linux Kernel UCSI driver allows local users to trigger an out-of-bounds access through a crafted CCI. ucsi_connector_change() indexes the connector array with a 7-bit value parsed by ucsi_notify_common() without checking it against the allocated connector count. Reachability requires a malicious or malfunctioning UCSI device to supply the bogus value, and the access can compromise kernel confidentiality, integrity, and availability.

The record

CVE
CVE-2026-31729
Published
May 1, 2026
Updated
May 1, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-129
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

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Is a vulnerable build present?

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

  1. Affected versionversion=5.5
  2. Affected versionversion=bdc62f2bae8fb0e8e99574de5232f0a3c54a27df <98429e9ec89a5e3a204112dfaa2dbe6ca28493a0
  3. Affected versionversion=bdc62f2bae8fb0e8e99574de5232f0a3c54a27df <d2d8c17ac01a1b1f638ea5d340a884ccc5015186
  4. Affected versionversion=bdc62f2bae8fb0e8e99574de5232f0a3c54a27df <f4e608fe12b7ac6a4a57176ab0296bb5a110a078
  5. Affected versionversion=bdc62f2bae8fb0e8e99574de5232f0a3c54a27df <f6dcbf2b024d55549959402f1db6c614e51d52cb

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.5; version=bdc62f2bae8fb0e8e99574de5232f0a3c54a27df <98429e9ec89a5e3a204112dfaa2dbe6ca28493a0; version=bdc62f2bae8fb0e8e99574de5232f0a3c54a27df <d2d8c17ac01a1b1f638ea5d340a884ccc5015186; version=bdc62f2bae8fb0e8e99574de5232f0a3c54a27df <f4e608fe12b7ac6a4a57176ab0296bb5a110a078; version=bdc62f2bae8fb0e8e99574de5232f0a3c54a27df <f6dcbf2b024d55549959402f1db6c614e51d52cb

Published CVSS scores

7.0Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5Oracle LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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-129Improper Validation of Array Index

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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