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AIKIDO-2026-729468

Mbed-TLS.mbedtls is vulnerable to Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)CVE-2026-34871 Published 3 days ago

30

Low Risk

This Affects:

c++Mbed-TLS.mbedtls
1.0.0 - 3.6.5
Fixed in 3.6.6
4.0.0 - 4.0.0
Fixed in 4.1.0
Are you affected? Scan for Free

TL;DR

On Linux, when the getrandom() system call is unavailable or blocked, Mbed TLS falls back to reading /dev/urandom, which can return data before the kernel entropy pool is initialized. On a freshly installed device without a hardware random generator, cryptographic operations performed early in boot may use predictable randomness. Keys and randomized ECDSA signatures generated during this window can be compromised. The fix avoids using /dev/urandom output before the system has gathered sufficient entropy.

Who does this affect?

You are affected if you are using a version that falls within the vulnerable range and your Linux device generates keys early in boot without a hardware random generator.

Background info

Mbed-TLS.mbedtls is vulnerable to Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) in versions 1.0.0 - 3.6.5 and 4.0.0 - 4.0.0.

How to fix this

Upgrade the Mbed-TLS.mbedtls library to the patch version.