CVE-2025-7396
📋 TL;DR
CVE-2025-7396 is a side-channel vulnerability in wolfSSL 5.8.2 where Curve25519 blinding is enabled by default only for C implementations, leaving ARM/Intel assembly builds and small Curve25519 feature implementations potentially vulnerable to timing attacks. This affects systems using wolfSSL for cryptographic operations with Curve25519 in non-C implementations. Attackers could theoretically extract private keys through physical access or side-channel observation.
💻 Affected Systems
- wolfSSL
📦 What is this software?
Wolfssl by Wolfssl
⚠️ Risk & Real-World Impact
Worst Case
Private key extraction from Curve25519 operations leading to complete compromise of encrypted communications and authentication mechanisms.
Likely Case
Minimal practical impact due to the difficulty of executing side-channel attacks requiring physical access or specialized equipment.
If Mitigated
No impact if using C implementation with blinding enabled or if system is not vulnerable to side-channel attacks.
🎯 Exploit Status
Exploitation requires physical access or sophisticated side-channel measurement equipment, making practical attacks difficult.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Update to wolfSSL version after 5.8.2
Vendor Advisory: https://github.com/wolfSSL/wolfssl/blob/master/ChangeLog.md#wolfssl-release-582-july-17-2025
Restart Required: Yes
Instructions:
1. Check current wolfSSL version. 2. Update to latest version after 5.8.2. 3. Recompile applications using wolfSSL. 4. Restart affected services.
🔧 Temporary Workarounds
Force C implementation
allConfigure wolfSSL to use C implementation of Curve25519 instead of assembly builds
./configure --enable-curve25519 --disable-asm
Disable Curve25519
allTemporarily disable Curve25519 if not required
./configure --disable-curve25519
🧯 If You Can't Patch
- Implement physical security controls to prevent side-channel observation
- Use alternative cryptographic algorithms not affected by this vulnerability
🔍 How to Verify
Check if Vulnerable:
Check wolfSSL version and configuration: if version is 5.8.2 and using ARM/Intel assembly or small Curve25519 feature.Check Version:
wolfssl_version --versionVerify Fix Applied:
Verify wolfSSL version is greater than 5.8.2 and check that Curve25519 blinding is properly configured.📡 Detection & Monitoring
Log Indicators:
- No specific log indicators for this side-channel vulnerability
Network Indicators:
- No network-based detection possible for physical side-channel attacks
SIEM Query:
Not applicable - physical side-channel attacks don't generate network logs