CVE-2025-66442

Weakness

In Mbed TLS through 4.0.0, there is a compiler-induced timing side channel (in RSA and CBC/ECB decryption) that only occurs with LLVM's select-optimize feature. TF-PSA-Crypto through 1.0.0 is also affected.

Affected products

• arm mbed_tls
• arm tf-psa-crypto

References

• https://github.com/Mbed-TLS/TF-PSA-Crypto/releases
• https://github.com/Mbed-TLS/mbedtls/releases
• https://mbed-tls.readthedocs.io/en/latest/security-advisories/
• https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2026-03-compiler-induced-constant-time-violations/