CVE-2025-66442
Mbed TLS through 4.0.0 vulnerability
Mbed · 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.
MSRC advisory May 19, 2026
Alert details
- Source feed
- Microsoft MSRC
- CVE ID
- CVE-2025-66442
- Affected products
- 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. · In 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. · In
What happened
Information published.
What it means for your business
In 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. (CVE-2025-66442) was added to Microsoft’s security update guidance. Information published. PremierePC tracks MSRC advisories for Upstate SC businesses — patch or open a ticket if you need help verifying exposure.
EPSS probability
0.27%
Sources
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