CVE-2021-20292

Kernel code execution via cleanup double free

Published May 28, 2021 · Updated Aug 3, 2024

Use-after-free in the Nouveau DRM subsystem in Linux Kernel before 5.9 allows local users with root privileges to execute kernel code. After page-table allocation fails, TTM invokes a destroy callback even though no page table exists, creating the reported double-free cleanup path. Reaching the path requires root and fault injection; hardened slab freelists prevent the reported effect, and upstream maintainers dispute the security analysis.

CVSS severity6.7
Medium
EPSS probability0.85%
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 the Nouveau DRM subsystem in Linux Kernel before 5.9 allows local users with root privileges to execute kernel code. After page-table allocation fails, TTM invokes a destroy callback even though no page table exists, creating the reported double-free cleanup path. Reaching the path requires root and fault injection; hardened slab freelists prevent the reported effect, and upstream maintainers dispute the security analysis.

The record

CVE
CVE-2021-20292
Published
May 28, 2021
Updated
Aug 3, 2024
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416, T1068
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. May 28, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record 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=Kernel 5.9

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linux Kernelversion=Kernel 5.9

Published CVSS scores

6.7NIST NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/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.

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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-416Use After Free
T1068Exploitation for Privilege Escalation

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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