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The vulnerability CVE-2025-7394 occurs in wolfSSL’s OpenSSL compatibility layer where the RAND_poll() function fails to properly reinitialize the random number generator state after a fork() system call. When an application calls fork() and then invokes RAND_bytes() in the child process without first calling RAND_poll(), the Hash-DRBG (Deterministic Random Bit Generator) is not reseeded. This results in the reuse of the same internal state across processes, leading to the generation of predictable or weakly random values. The issue specifically affects applications that explicitly use RAND_bytes() after fork() for cryptographic operations, such as key generation or nonce creation, compromising security. wolfSSL has addressed this by modifying RAND_bytes() to automatically detect fork() events and reseed the DRBG, aligning with OpenSSL’s behavior. Internal TLS mechanisms within wolfSSL remain unaffected.
Platform: wolfSSL
Version: Prior to fix
Vulnerability: Predictable random numbers
Severity: Critical
Date: 07/18/2025
Prediction: Patch released 07/2025
What Undercode Say:
Showing bash commands and codes related to the blog
Bash command to check wolfSSL version: `wolfssl-config –version`
Code snippet demonstrating vulnerable pattern:
include <wolfssl/openssl/rand.h>
include <unistd.h>
int main() {
pid_t pid = fork();
if (pid == 0) {
unsigned char buffer[bash];
RAND_bytes(buffer, sizeof(buffer));
}
return 0;
}
how Exploit:
Attacker predicts random numbers after fork, compromising cryptographic keys.
Protection from this CVE:
Update wolfSSL version.
Impact:
Weak encryption, insecure keys.
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Sources:
Reported By: nvd.nist.gov
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