CVE-2025-66442 Affecting mbedtls package, versions *
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-DEBIANUNSTABLE-MBEDTLS-15929478
- published8 Apr 2026
- disclosed1 Apr 2026
Introduced: 1 Apr 2026
CVE-2025-66442 (opens in a new tab)How to fix?
There is no fixed version for Debian:unstable mbedtls.
NVD Description
Note: Versions mentioned in the description apply only to the upstream mbedtls package and not the mbedtls package as distributed by Debian.
See How to fix? for Debian:unstable relevant fixed versions and status.
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
- https://security-tracker.debian.org/tracker/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/