CVE-2021-47576

Kernel compromise via unchecked block-descriptor length

Published Jun 19, 2024 · Updated Aug 5, 2026

Use-after-free in Linux 2.6.19 through 5.15.10 allows local users with writable scsi_debug device access to compromise the kernel. resp_mode_select() trusts the MODE SELECT block-descriptor length, computes an offset beyond the copied parameter buffer, and reads arr[off] without first proving the offset is in bounds. Exploitation requires local write access to a SCSI generic node backed by the scsi_debug virtual adapter; the resulting kernel-memory access can disclose data, corrupt kernel state, or panic the host.

CVSS severity7.8
High
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux 2.6.19 through 5.15.10 allows local users with writable scsi_debug device access to compromise the kernel. resp_mode_select() trusts the MODE SELECT block-descriptor length, computes an offset beyond the copied parameter buffer, and reads arr[off] without first proving the offset is in bounds. Exploitation requires local write access to a SCSI generic node backed by the scsi_debug virtual adapter; the resulting kernel-memory access can disclose data, corrupt kernel state, or panic the host.

The record

CVE
CVE-2021-47576
Published
Jun 19, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 19, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=231839102b54512ced7d3ee7fc9b8bcf5e3b583b <04181973c38f3d6a353f9246dcf7fee08024fd9e
  2. Affected versionversion=231839102b54512ced7d3ee7fc9b8bcf5e3b583b <90491283b4064220682e4b0687d07b05df01e3bf
  3. Affected versionversion=231839102b54512ced7d3ee7fc9b8bcf5e3b583b <a9078e791426c2cbbdf28a320c3670f6e0a611e6
  4. Affected versionversion=231839102b54512ced7d3ee7fc9b8bcf5e3b583b <adcecd50da6cab7b4957cba0606771dcc846c5a9
  5. Affected versionversion=231839102b54512ced7d3ee7fc9b8bcf5e3b583b <b847ecff850719c46c95acd25a0d555dfd16e10d
  6. Affected versionversion=231839102b54512ced7d3ee7fc9b8bcf5e3b583b <dfc3fff63793c571147930b13c0f8c689c4281ac
  7. Affected versionversion=231839102b54512ced7d3ee7fc9b8bcf5e3b583b <e0a2c28da11e2c2b963fc01d50acbf03045ac732
  8. Affected versionversion=2.6.19

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=231839102b54512ced7d3ee7fc9b8bcf5e3b583b <04181973c38f3d6a353f9246dcf7fee08024fd9e; version=231839102b54512ced7d3ee7fc9b8bcf5e3b583b <90491283b4064220682e4b0687d07b05df01e3bf; version=231839102b54512ced7d3ee7fc9b8bcf5e3b583b <a9078e791426c2cbbdf28a320c3670f6e0a611e6; version=231839102b54512ced7d3ee7fc9b8bcf5e3b583b <adcecd50da6cab7b4957cba0606771dcc846c5a9; version=231839102b54512ced7d3ee7fc9b8bcf5e3b583b <b847ecff850719c46c95acd25a0d555dfd16e10d; version=231839102b54512ced7d3ee7fc9b8bcf5e3b583b <dfc3fff63793c571147930b13c0f8c689c4281ac; version=231839102b54512ced7d3ee7fc9b8bcf5e3b583b <e0a2c28da11e2c2b963fc01d50acbf03045ac732; version=2.6.19

Published CVSS scores

7.8Linux CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1068Exploitation for Privilege Escalation

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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