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 occurs with LLVM's select-optimize feature. TF-PSA-Crypto through 1.0.0 is also affected.

Overview

Severity

Medium (CVSS 5.1)

CVSS Vector

CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Exploit Status

Not Exploited

Patch Tuesday

2026-Apr

Released

2026-05-07

Last Updated

2026-09-03

EPSS Score

0.27% (percentile: 17.1%)

Affected Products (1)

Other

• 21780-17084

Security Updates (1)

• Security Update

Revision History

• 2026-05-07: Information published.
• 2026-05-19: Information published.
• 2026-05-31: Information published.
• 2026-06-01: Information published.
• 2026-06-02: Information published.
• 2026-09-03: Information published.