CVE-2026-74694

Kernel heap disclosure via unchecked NCSI payload length

Published Aug 22, 2026 · Updated Aug 22, 2026

Out-of-bounds read in Linux 4.20 and later allows local users to expose kernel heap data through crafted NCSI netlink commands. ncsi_send_cmd_nl trusts the header's declared length without checking it against the NCSI_ATTR_DATA payload, so ncsi_cmd_handler_oem copies beyond the attribute buffer. Access requires CAP_NET_ADMIN and a registered NCSI device; one malformed command can transmit about 64 KB of adjacent kernel heap data.

CVSS severityUnavailable
Unscored
EPSS probability0.18%
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 Linux 4.20 and later allows local users to expose kernel heap data through crafted NCSI netlink commands. ncsi_send_cmd_nl trusts the header's declared length without checking it against the NCSI_ATTR_DATA payload, so ncsi_cmd_handler_oem copies beyond the attribute buffer. Access requires CAP_NET_ADMIN and a registered NCSI device; one malformed command can transmit about 64 KB of adjacent kernel heap data.

The record

CVE
CVE-2026-74694
Published
Aug 22, 2026
Updated
Aug 22, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-20, CWE-787
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Aug 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 22, 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=4.20
  2. Affected versionversion=9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 <02226af69362758046822840fc6a497f5de33f00
  3. Affected versionversion=9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 <3a60b5af75abe8e3494ccd074fb4ae6e601a3e55
  4. Affected versionversion=9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 <43c7d0a6917751ea898ae584d00f24f5deac46d4
  5. Affected versionversion=9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 <4489b4a17892750131e4bef4bc1d3d703c8fb5ba
  6. Affected versionversion=9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 <67c72b8ef63d9d9a610546fda30b116638f39745
  7. Affected versionversion=9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 <afa58b7384913c8773d837acdb07b035690ec5d2
  8. Affected versionversion=9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 <b5231ad0b376b801ab8cf2962b182cc29deaedb3
  9. Affected versionversion=9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 <e60afa01d35f8b2671b27ca93309921427144cce

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=4.20; version=9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 <02226af69362758046822840fc6a497f5de33f00; version=9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 <3a60b5af75abe8e3494ccd074fb4ae6e601a3e55; version=9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 <43c7d0a6917751ea898ae584d00f24f5deac46d4; version=9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 <4489b4a17892750131e4bef4bc1d3d703c8fb5ba; version=9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 <67c72b8ef63d9d9a610546fda30b116638f39745; version=9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 <afa58b7384913c8773d837acdb07b035690ec5d2; version=9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 <b5231ad0b376b801ab8cf2962b182cc29deaedb3; version=9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 <e60afa01d35f8b2671b27ca93309921427144cce

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
CWE-787Out-of-bounds Write

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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