CVE-2025-66442 The advisory has been revoked - it doesn't affect any version of package mbedtls (opens in a new tab)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-UBUNTU1604-MBEDTLS-15926529
- published15 Apr 2026
- disclosed1 Apr 2026
Introduced: 1 Apr 2026
CVE-2025-66442 (opens in a new tab)Amendment
The Ubuntu security team deemed this advisory irrelevant for Ubuntu:16.04.
NVD Description
Note: Versions mentioned in the description apply only to the upstream mbedtls package and not the mbedtls package as distributed by Ubuntu.
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.
References
- http://people.ubuntu.com/~ubuntu-security/cve/CVE-2025-66442
- 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/