Vulnerability in Arm Mbed_tls
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.
EPSS: 0.003 (18.9th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.1 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N.
Affected products
- Arm Mbed_tls
- Arm Tf-psa-crypto
- N/a — versions n/a
Weakness classification (CWE)
References
- cve@mitre.org (Release Notes)
- cve@mitre.org (Vendor Advisory)
- cve@mitre.org (Release Notes)
- cve@mitre.org (Vendor Advisory)
Frequently asked questions
- What is CVE-2025-66442?
- CVE-2025-66442 is a medium-severity vulnerability in Arm Mbed_tls, classified under CWE-385. CVSS score: 5.1/10. Published 2026-04-01.
- How severe is CVE-2025-66442?
- Medium severity. CVSS v3 base score is 5.1 out of 10.