CVE-2021-47087

Local privilege escalation via shifted page free

Published Mar 4, 2024 · Updated Aug 5, 2026

Invalid page release in the Linux OP-TEE driver allows local users to corrupt kernel memory through a shared-memory allocation request. The allocation error path advances its struct page pointer, then passes that shifted pointer to __free_pages(), releasing unrelated pages. Reachability requires local access to /dev/tee devices and TEE_IOC_SHM_ALLOC; the resulting corruption permits kernel reads, writes, control-flow hijacking, or a system crash.

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

What happened

Invalid page release in the Linux OP-TEE driver allows local users to corrupt kernel memory through a shared-memory allocation request. The allocation error path advances its struct page pointer, then passes that shifted pointer to __free_pages(), releasing unrelated pages. Reachability requires local access to /dev/tee devices and TEE_IOC_SHM_ALLOC; the resulting corruption permits kernel reads, writes, control-flow hijacking, or a system crash.

The record

CVE
CVE-2021-47087
Published
Mar 4, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-763, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 4, 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=1340dc3fb75ea69221f4f5dcb0cbace55ad0331c <ad338d825e3f7b96ee542bf313728af2d19fe9ad
  2. Affected versionversion=255e17923b22cb7abd026e044416d61f6bd0eec0
  3. Affected versionversion=3c712f14d8a9354a8807c15c64c8dd334499cc42 <806142c805cacd098e61bdc0f72c778a2389fe4a
  4. Affected versionversion=5.10.58 <5.10.89
  5. Affected versionversion=5.13.10 <5.14
  6. Affected versionversion=5.14
  7. Affected versionversion=5.4.140 <5.4.169
  8. Affected versionversion=ec185dd3ab257dc2a60953fdf1b6622f524cc5b7 <18549bf4b21c739a9def39f27dcac53e27286ab5
  9. Affected versionversion=ec185dd3ab257dc2a60953fdf1b6622f524cc5b7 <91e94e42f6fc49635f1a16d8ae3f79552bcfda29

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1340dc3fb75ea69221f4f5dcb0cbace55ad0331c <ad338d825e3f7b96ee542bf313728af2d19fe9ad; version=255e17923b22cb7abd026e044416d61f6bd0eec0; version=3c712f14d8a9354a8807c15c64c8dd334499cc42 <806142c805cacd098e61bdc0f72c778a2389fe4a; version=5.10.58 <5.10.89; version=5.13.10 <5.14; version=5.14; version=5.4.140 <5.4.169; version=ec185dd3ab257dc2a60953fdf1b6622f524cc5b7 <18549bf4b21c739a9def39f27dcac53e27286ab5; version=ec185dd3ab257dc2a60953fdf1b6622f524cc5b7 <91e94e42f6fc49635f1a16d8ae3f79552bcfda29

Published CVSS scores

7.8Linux kernel CVE teamCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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.

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-763Release of Invalid Pointer or Reference
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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