CVE-2021-47647

System crash via missing PCIe clock parent

Published Feb 26, 2025 · Updated May 11, 2026

NULL pointer dereference in the Qualcomm IPQ8074 clock driver in affected Linux 5.x kernels allows local users to crash the system. The pcie0_rchng_clk_src definition declares two parents but supplies only one through parent_hws, causing clk_core_get_parent_by_index() to dereference NULL during clock registration. Reachability requires the IPQ8074 driver and PCIe clock initialization; the resulting panic can reset the board before serial initialization, with no reported data disclosure or modification.

CVSS severity5.5
Medium
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in the Qualcomm IPQ8074 clock driver in affected Linux 5.x kernels allows local users to crash the system. The pcie0_rchng_clk_src definition declares two parents but supplies only one through parent_hws, causing clk_core_get_parent_by_index() to dereference NULL during clock registration. Reachability requires the IPQ8074 driver and PCIe clock initialization; the resulting panic can reset the board before serial initialization, with no reported data disclosure or modification.

The record

CVE
CVE-2021-47647
Published
Feb 26, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 26, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=5.9
  2. Affected versionversion=f0cfcf1ade201dcfd3365f231efc90e846fa46df <41e360fa73a4c2f5b78f5ded78a5375b08c206a5
  3. Affected versionversion=f0cfcf1ade201dcfd3365f231efc90e846fa46df <5a5576ad405c3c89fc9afb245c4dcc3e412b0aa9
  4. Affected versionversion=f0cfcf1ade201dcfd3365f231efc90e846fa46df <8b89c9e68a01a19a1dd689a42aa65d545e931899
  5. Affected versionversion=f0cfcf1ade201dcfd3365f231efc90e846fa46df <bf8f5182b8f59309809b41c1d1730ed9ca6134b1
  6. Affected versionversion=f0cfcf1ade201dcfd3365f231efc90e846fa46df <d02b3d4a8c525068bc5cfb4341e0023d8eb82ace

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.9; version=f0cfcf1ade201dcfd3365f231efc90e846fa46df <41e360fa73a4c2f5b78f5ded78a5375b08c206a5; version=f0cfcf1ade201dcfd3365f231efc90e846fa46df <5a5576ad405c3c89fc9afb245c4dcc3e412b0aa9; version=f0cfcf1ade201dcfd3365f231efc90e846fa46df <8b89c9e68a01a19a1dd689a42aa65d545e931899; version=f0cfcf1ade201dcfd3365f231efc90e846fa46df <bf8f5182b8f59309809b41c1d1730ed9ca6134b1; version=f0cfcf1ade201dcfd3365f231efc90e846fa46df <d02b3d4a8c525068bc5cfb4341e0023d8eb82ace

Published CVSS scores

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.

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

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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