CVE-2021-47142

Kernel crash via stale scatter-gather pointer

Published Mar 25, 2024 · Updated Aug 5, 2026

Use-after-free in affected Linux kernel branches beginning with 4.2 allows local users to crash the kernel through an AMDGPU allocation ioctl. The amdgpu_ttm_backend_unbind function frees the scatter-gather table but leaves ttm->sg pointing at freed memory, so later cleanup frees the stale table again. The path requires local access to the AMDGPU KFD memory-allocation ioctl on a supported AMD GPU; triggering it causes a kernel panic and host service interruption.

CVSS severity7.8
High
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Use-after-free in affected Linux kernel branches beginning with 4.2 allows local users to crash the kernel through an AMDGPU allocation ioctl. The amdgpu_ttm_backend_unbind function frees the scatter-gather table but leaves ttm->sg pointing at freed memory, so later cleanup frees the stale table again. The path requires local access to the AMDGPU KFD memory-allocation ioctl on a supported AMD GPU; triggering it causes a kernel panic and host service interruption.

The record

CVE
CVE-2021-47142
Published
Mar 25, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 25, 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

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=4.2
  2. Affected versionversion=d38ceaf99ed015f2a0b9af3499791bd3a3daae21 <0707c3fea8102d211631ba515ef2159707561b0d
  3. Affected versionversion=d38ceaf99ed015f2a0b9af3499791bd3a3daae21 <1e5c37385097c35911b0f8a0c67ffd10ee1af9a2
  4. Affected versionversion=d38ceaf99ed015f2a0b9af3499791bd3a3daae21 <3293cf3513d69f00c14d43e2020826d45ea0e46a
  5. Affected versionversion=d38ceaf99ed015f2a0b9af3499791bd3a3daae21 <7398c2aab4da960761ec182d04d6d5abbb4a226e
  6. Affected versionversion=d38ceaf99ed015f2a0b9af3499791bd3a3daae21 <952ab3f9f48eb0e8050596d41951cf516be6b122
  7. Affected versionversion=d38ceaf99ed015f2a0b9af3499791bd3a3daae21 <a849e218556f932576c0fb1c5a88714b61709a17
  8. Affected versionversion=d38ceaf99ed015f2a0b9af3499791bd3a3daae21 <d4ea141fd4b40636a8326df5a377d9c5cf9b3faa
  9. Affected versionversion=d38ceaf99ed015f2a0b9af3499791bd3a3daae21 <f98cdf084405333ee2f5be548a91b2d168e49276

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.2; version=d38ceaf99ed015f2a0b9af3499791bd3a3daae21 <0707c3fea8102d211631ba515ef2159707561b0d; version=d38ceaf99ed015f2a0b9af3499791bd3a3daae21 <1e5c37385097c35911b0f8a0c67ffd10ee1af9a2; version=d38ceaf99ed015f2a0b9af3499791bd3a3daae21 <3293cf3513d69f00c14d43e2020826d45ea0e46a; version=d38ceaf99ed015f2a0b9af3499791bd3a3daae21 <7398c2aab4da960761ec182d04d6d5abbb4a226e; version=d38ceaf99ed015f2a0b9af3499791bd3a3daae21 <952ab3f9f48eb0e8050596d41951cf516be6b122; version=d38ceaf99ed015f2a0b9af3499791bd3a3daae21 <a849e218556f932576c0fb1c5a88714b61709a17; version=d38ceaf99ed015f2a0b9af3499791bd3a3daae21 <d4ea141fd4b40636a8326df5a377d9c5cf9b3faa; version=d38ceaf99ed015f2a0b9af3499791bd3a3daae21 <f98cdf084405333ee2f5be548a91b2d168e49276

Published CVSS scores

7.8Linux kernel CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5NIST NVDCVSS: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 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
T1499.004Endpoint Denial of Service: Application or System Exploitation

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo