Description
OP-TEE OS through 4.10.0, fixed in commit 7b8b494, contains a buffer underwrite vulnerability in the RSA NOPAD encrypt and decrypt operations within the mbedTLS software backend and SE050 hardware driver that allows a malicious Trusted Application to corrupt secure-world heap memory by supplying an input length exceeding the RSA modulus size. When src_len exceeds rsa_len, the subtraction expression wraps to a large unsigned value, causing a subsequent memcpy to write attacker-controlled data before the destination buffer in S-EL1 secure-world heap memory.
Published: 2026-08-10
Score: 8.4 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

OP‑TEE OS versions up to 4.10.0 contain a buffer underwrite in the mbedTLS RSA NOPAD encrypt and decrypt functions. When a Trusted Application supplies an input length larger than the RSA modulus, a signed subtraction wraps to a large unsigned value, and a subsequent memcpy writes before the destination buffer in secure‑world heap memory. This results in uncontrolled modification of heap objects and can compromise confidentiality and integrity of the secure world.

Affected Systems

The affected products are OP‑TEE OS (optee_os) version 4.10.0 and earlier. The issue is fixed in commit 7b8b494e0a324cefec8ed386b7de413b44f1aaf3, which should be present in newer releases.

Risk and Exploitability

The CVSS score of 8.4 indicates high severity. EPSS data is not available, and the vulnerability is not cataloged in the CISA KEV list. The exploit requires a malicious Trusted Application running in the secure world; the attack vector is local, targeting the buffer boundary during RSA operations. Successful exploitation could corrupt heap structures and alter program control flow within the secure world.

Generated by OpenCVE AI on August 10, 2026 at 19:50 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Upgrade to a patched OP‑TEE OS release that includes commit 7b8b494 or newer.
  • If upgrading is not immediately possible, restrict the installation of untrusted Trusted Applications and disable RSA NOPAD operations when not required.
  • Implement runtime checks or policy enforcement to validate RSA input lengths, rejecting any that exceed the modulus size.

Generated by OpenCVE AI on August 10, 2026 at 19:50 UTC.

Tracking

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Advisories

No advisories yet.

History

Mon, 10 Aug 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Mon, 10 Aug 2026 18:45:00 +0000

Type Values Removed Values Added
Description OP-TEE OS through 4.10.0, fixed in commit 7b8b494, contains a buffer underwrite vulnerability in the RSA NOPAD encrypt and decrypt operations within the mbedTLS software backend and SE050 hardware driver that allows a malicious Trusted Application to corrupt secure-world heap memory by supplying an input length exceeding the RSA modulus size. When src_len exceeds rsa_len, the subtraction expression wraps to a large unsigned value, causing a subsequent memcpy to write attacker-controlled data before the destination buffer in S-EL1 secure-world heap memory.
Title OP-TEE OS 4.10.0 Buffer Underwrite via RSA NOPAD Encrypt/Decrypt Operations
Weaknesses CWE-124
CWE-787
References
Metrics cvssV3_1

{'score': 6.7, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 8.4, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

Subscriptions

No data.

cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-08-10T19:47:52.137Z

Reserved: 2026-08-08T16:43:04.178Z

Link: CVE-2026-71969

cve-icon Vulnrichment

Updated: 2026-08-10T19:47:48.409Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-10T20:00:03Z

Weaknesses
  • CWE-124

    Buffer Underwrite ('Buffer Underflow')

  • CWE-787

    Out-of-bounds Write