CVE-2025-66442

EUVD-2025-209171
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
5.1 MEDIUM
LOCAL
HIGH
NONE
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: 6%
Affected Products (NVD)
VendorProductVersion
armmbed_tls
𝑥
≤ 4.0.0
armtf-psa-crypto
𝑥
≤ 1.0.0
𝑥
= Vulnerable software versions
Common Weakness Enumeration
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/