OP-TEE OS CVE-2026-71969

Exploitation requires the ability to load and execute a Trusted Application within the OP-TEE secure world at S-EL0. In production deployments with enforced TA signing (hardware-protected signing key), an attacker must obtain or forge a valid TA signature before reaching the vulnerable code - a significant prerequisite. The vulnerable entry points are specifically the RSA NOPAD encrypt and decrypt operations (rsanopad_encrypt, rsanopad_decrypt) in either the mbedTLS backend or the SE050 hardware driver; only TAs that invoke these primitives via the TEE internal cryptographic API trigger the flaw. Exploitation is limited by: (1) the requirement to execute trusted code at S-EL0, which implies some form of pre-existing privileged access or supply-chain compromise; (2) TA signing enforcement in hardened production environments; and (3) an entirely local attack vector with no network-reachable trigger. In development environments, debug builds, or platforms configured to accept unsigned or developer-signed TAs, the barrier is substantially lower and exploitation requires only knowledge of the API.

The provided CVSS 4.0 score of 8.4 reflects a meaningful real-world barrier: PR:H indicates that exploitation requires executing code as a Trusted Application inside the TEE, and AV:L confirms the entirely local attack vector with no remote trigger path. Full CIA impact (VC:H/VI:H/VA:H) within the secure world is realistic once the attacker controls a TA, as S-EL1 heap corruption can overwrite function pointers, metadata, or cryptographic key material. SC:N/SI:N/SA:N indicates the assessment treats impact as contained to OP-TEE OS itself, though defenders should independently assess whether TEE compromise in their architecture weakens normal-world trust assumptions. No EPSS data was available, so exploitation probability is unknown. The absence of a CISA KEV listing means no confirmed active exploitation. The dual-path nature of the flaw (mbedTLS and SE050) means the attack surface is not limited by hardware configuration. Risk is elevated in development environments or platforms permitting unsigned TA deployment, and substantially reduced in production systems with enforced TA signing. No public exploit has been identified at time of analysis, consistent with this being a low-to-medium real-world priority outside of TEE-focused adversaries.

An insider or supply-chain attacker with TA signing capability deploys a malicious Trusted Application that calls the rsanopad_encrypt or rsanopad_decrypt interface with an input buffer whose byte length exceeds the RSA key modulus size. The absent bounds check causes the unsigned subtraction to wrap, and the resulting oversized memcpy overwrites secure-world heap metadata or function pointers in S-EL1 memory with attacker-controlled bytes, enabling potential code execution at TEE OS privilege or extraction of cryptographic key material held in the secure heap. No public exploit code has been identified at time of analysis.