CVE-2025-66442: In Mbed TLS through 4.0.0, there is a compiler-induced timing side channel (in RSA and CBC/ECB decryption) that only…
CVE-2025-66442 · Severity: medium · CVSS 5.1 · Published 2026-04-01
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.
No. Junglewise Threat Intelligence has no report of CVE-2025-66442 being exploited in the wild.
How severe is CVE-2025-66442?
Medium severity, with a CVSS score of 5.1, published 1 April 2026.
Which products and versions are affected?
Arm Mbed Tls, Arm Tf-Psa-Crypto. The advisory does not name versions.
Is there a fix for CVE-2025-66442?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
Am I affected by CVE-2025-66442?
Check whether you run Arm Mbed Tls or Arm Tf-Psa-Crypto. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.