CVE-2025-66442 Information disclosure in n/a

What is CVE-2025-66442?

CVE-2025-66442 is a medium-severity vulnerability in Arm Mbed Tls, published on 1 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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.

Weakness: CWE-385

Which versions are affected by CVE-2025-66442?

It affects 2 products.

Products include Arm Mbed Tls, Arm Tf-Psa-Crypto.

How do I fix CVE-2025-66442?

No fix has been published for CVE-2025-66442 yet. Limit exposure of the affected software until one is available.

Is CVE-2025-66442 being exploited?

There is no known exploitation of CVE-2025-66442 in the wild and no public exploit code.

Other vulnerabilities in Arm Mbed Tls

• CVE-2026-34877 Deserialization in n/a Critical 9.8
• CVE-2022-46393 Memory corruption in n/a Critical 9.8
• CVE-2021-44732 Use after free in n/a Critical 9.8
• CVE-2017-18187 Integer overflow in n/a Critical 9.8
• CVE-2018-0487 Memory corruption in ARM mbed TLS before 1.3.22, before 2.1.10, and before 2.7.0 Critical 9.8

All Arm Mbed Tls vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2025-66442, GHSA-56v8-wv3m-qgg6, JLSEC-2026-463, UBUNTU-CVE-2025-66442.