CVE-2026-71969: op-tee optee_os Buffer Underflow

Vulnerability summary

CVE-2026-71969 is a high (CVSS 8.4) Buffer Underflow vulnerability in op-tee optee_os. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 7.3% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 10-08-2026
   PublishedVulnerability first disclosed.
2. 17-08-2026
   Last modifiedVulnerability information updated.

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.

• CWE-124Buffer Underwrite ('Buffer Underflow')The product writes to a buffer using an index or pointer that references a memory location prior to the beginning of the buffer.
• CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.