CVE-2021-47483

Kernel memory corruption via stale regmap pointer

Published May 22, 2024 · Updated Aug 5, 2026

Double-free in the Linux kernel regmap cache allows local users to corrupt kernel memory during driver initialization. If the present-bitmap reallocation fails, regcache_rbtree_insert_to_block frees blk without first updating rbnode->block, leaving a stale pointer. Reachability requires local access and a regmap-backed driver initialization path with the allocation failure; cleanup frees the stale pointer again and can crash the system.

CVSS severity7.8
High
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Double-free in the Linux kernel regmap cache allows local users to corrupt kernel memory during driver initialization. If the present-bitmap reallocation fails, regcache_rbtree_insert_to_block frees blk without first updating rbnode->block, leaving a stale pointer. Reachability requires local access and a regmap-backed driver initialization path with the allocation failure; cleanup frees the stale pointer again and can crash the system.

The record

CVE
CVE-2021-47483
Published
May 22, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-415
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 22, 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=3.12
  2. Affected versionversion=3f4ff561bc88b074d5e868dde4012d89cbb06c87 <1cead23c1c0bc766dacb900a3b0269f651ad596f
  3. Affected versionversion=3f4ff561bc88b074d5e868dde4012d89cbb06c87 <36e911a16b377bde0ad91a8c679069d0d310b1a6
  4. Affected versionversion=3f4ff561bc88b074d5e868dde4012d89cbb06c87 <3dae1a4eced3ee733d7222e69b8a55caf2d61091
  5. Affected versionversion=3f4ff561bc88b074d5e868dde4012d89cbb06c87 <50cc1462a668dc62949a1127388bc3af785ce047
  6. Affected versionversion=3f4ff561bc88b074d5e868dde4012d89cbb06c87 <55e6d8037805b3400096d621091dfbf713f97e83
  7. Affected versionversion=3f4ff561bc88b074d5e868dde4012d89cbb06c87 <758ced2c3878ff789801e6fee808e185c5cf08d6
  8. Affected versionversion=3f4ff561bc88b074d5e868dde4012d89cbb06c87 <e72dce9afbdbfa70d9b44f5908a50ff6c4858999
  9. Affected versionversion=3f4ff561bc88b074d5e868dde4012d89cbb06c87 <fc081477b47dfc3a6cb50a96087fc29674013fc2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3.12; version=3f4ff561bc88b074d5e868dde4012d89cbb06c87 <1cead23c1c0bc766dacb900a3b0269f651ad596f; version=3f4ff561bc88b074d5e868dde4012d89cbb06c87 <36e911a16b377bde0ad91a8c679069d0d310b1a6; version=3f4ff561bc88b074d5e868dde4012d89cbb06c87 <3dae1a4eced3ee733d7222e69b8a55caf2d61091; version=3f4ff561bc88b074d5e868dde4012d89cbb06c87 <50cc1462a668dc62949a1127388bc3af785ce047; version=3f4ff561bc88b074d5e868dde4012d89cbb06c87 <55e6d8037805b3400096d621091dfbf713f97e83; version=3f4ff561bc88b074d5e868dde4012d89cbb06c87 <758ced2c3878ff789801e6fee808e185c5cf08d6; version=3f4ff561bc88b074d5e868dde4012d89cbb06c87 <e72dce9afbdbfa70d9b44f5908a50ff6c4858999; version=3f4ff561bc88b074d5e868dde4012d89cbb06c87 <fc081477b47dfc3a6cb50a96087fc29674013fc2

Published CVSS scores

7.8NIST NVDCVSS: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

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-415Double Free

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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