What’s Vulnerable › Vulnerabilities

CVE-2025-66442

• Severity: medium (CVSS 5.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-01 · updated 2026-06-17
• Weakness: CWE-385

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.

Affected products

• mbedtls: through 4.0.0
• Arm Tf-Psa-Crypto: through 1.0.0

References

• 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/

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