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CVE Record

CVE-2021-47087: tee: optee: Fix incorrect page free bug

In the Linux kernel, the following vulnerability has been resolved: tee: optee: Fix incorrect page free bug Pointer to the allocated pages (struct page *page) has already progressed towards the end of allocation. It is incorrect to perform __free_pages(page, order) using this pointer as we would free any arbitrary pages. Fix this by stop modifying the page pointer.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2021-47087 is a Linux kernel bug in the OP-TEE driver where the kernel could free the wrong memory pages. The public record does not provide a CVSS score or confirmed exploitation. Business urgency depends on whether affected kernels and OP-TEE support are present in your Linux fleet.

Executive priority

Track this as a kernel maintenance item with environment-dependent urgency. Escalate for embedded, appliance, or trusted-execution deployments using affected kernels. Without confirmed exploitation or severity scoring, broad emergency action is not supported by the provided evidence.

Technical view

The resolved bug is in tee/optee page handling. A struct page pointer was advanced during allocation handling, then reused in __free_pages(page, order), which could free arbitrary pages. Stable kernel fixes stop modifying the page pointer before freeing. The sources identify Linux kernel impact, but do not describe exploit primitives or attacker prerequisites.

Likely exposure

Exposure is most likely on Linux systems running affected kernel versions with OP-TEE/TEE functionality in use or enabled. The CVE data lists Linux versions including 5.14, 5.4.169, 5.10.89, 5.15.12, and 5.16. Distro backports may change practical exposure.

Exploitation context

The provided sources do not state active exploitation, public exploit availability, attacker access requirements, or observed abuse. The CVE is not listed as KEV in the supplied bundle. Treat exploitation status as unconfirmed, not absent.

Researcher notes

The public description is concise and fix-oriented. It indicates a wrong-page-free condition caused by mutating the page pointer before __free_pages. The bundle lacks CVSS, CWE, exploitability analysis, and runtime trigger details, so validation should focus on code lineage and vendor backport status.

Mitigation direction

  • Apply vendor or distribution kernel updates containing the referenced stable fixes.
  • Check vendor advisories for backported fixes before relying on upstream version numbers.
  • Prioritize systems using OP-TEE or TEE features for review and patching.
  • If no patch is available, request specific guidance from the kernel or platform vendor.

Validation and detection

  • Inventory Linux kernel versions across servers, appliances, and embedded platforms.
  • Confirm whether OP-TEE or TEE kernel support is enabled or loaded.
  • Verify the relevant stable fix commits are present or backported.
  • Review vendor kernel changelogs for CVE-2021-47087 or the referenced commit IDs.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2021-47087 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
2ADP providers
5Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux3c712f14d8a9354a8807c15c64c8dd334499cc42, 1340dc3fb75ea69221f4f5dcb0cbace55ad0331c, ec185dd3ab257dc2a60953fdf1b6622f524cc5b7, ec185dd3ab257dc2a60953fdf1b6622f524cc5b7, 255e17923b22cb7abd026e044416d61f6bd0eec0unaffected
LinuxLinux5.14, 0, 5.4.169, 5.10.89, 5.15.12, 5.16affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.